Stock appearing 425hp 383 possible?

Re: Stock appearing 425hp 383 possible? - 10/13/12 07:04 PM

There's nothing about your parameters that would steer me away from building a 451. 440's make good power with stock manifolds, why not in a lowdeck block. Mine appears nearly stock and makes over 500hp. subtract headers and substitute a DP4B, and I'm right there in your wheelhouse.

I'd go with a solid flat tappet cam in 250 - 255 duration range; use a set of Eddy or source heads (if you're truly looking for the stock vibe), and an 850 holley up top, and I guarantee you'd be in the ballpark and be reasonably streetable. Getting an honest 450 horse out of a stock stroke 383 will mean a much more high strung motor that won't be as pleasant to drive.

Posted By: BSB67

Re: Stock appearing 425hp 383 possible? - 10/13/12 07:12 PM

The more cu. in., the better. Why? You can put a bigger cam in while retaining a stock like idle. Unless you are under budget constraints, it would be silly to use a stock stroke 383 if you are looking to maximize power. Here is an option:

451 cu.in
Ported Stealth's
10.5:1 CR
Custom ground cam
Divider removed from DP4B
2 1/2" TTI and Ultra Flows

Easy 450 hp with a hydraulic cam, and never open the hood again. Or 500 hp with an agressive cam. All on pump gas.

Posted By: Cab_Burge

Re: Stock appearing 425hp 383 possible? - 10/13/12 07:14 PM

Quote:

Quote:

Why is stroking out of the question?

My intake and exhaust manifolds are limiting factors... I don't want them choking the extra cubes. I'm also building a clone and starting with nothing... I could build a 440 if I wanted too, but I want the smaller displacement faster revving engine.

I hoping to fit the car with the one of the new Passon 5-speeds, with a 4.10 Sure Grip out back.

I'm also not opposed to aluminum heads vs. ported stock. I'm looking at "gasp" Stealth heads (I'm fully aware of their issues with valve locks) for no other reason other than that they appear fairly stock on the outside.

In my opinion you are looking at the stroke wrong, the stock exhaust manifolds and intake limit the peak torrque and HP RPM,I would at least think of using a 440 crank on your build

That makes it act like a 426W

Or better yet a 440 crank offset ground to 3.91 stroke and use the BB Chevy rod journal size and cheaper good quality H bem steel rods

The 400 block with either the 440 crank or the offset stroke 3.91 crank will make a really good combination for what your doing

I've made 500+ HP with a pump gas 440 based stock stroke motor with iron heads a bunch of times, add a set of aluminum heads and 540 HP gets in sight very easily

Good luck on your build, it is very smart to think of what to do and use before starting

Posted By: Twostick

Re: Stock appearing 425hp 383 possible? - 10/13/12 07:24 PM

Don't write off a stroker just because you want to keep your manifolds. Just need to pick the right cam for the application. Displacement is your friend.

I would do the 400 stroked to 496. CNC Stealths with dished flat tops zero decked for 9:1. With a cam ground with HP manifolds in mind (see Dwayne Porter or AndyF) you should knock hard on 500hp/600ft/lbs and be all done by 5000 RPM. Nice street engine and only needs 87 regular gas to boot.

Kevin

Posted By: topside

Re: Stock appearing 425hp 383 possible? - 10/13/12 07:47 PM

425HP is not at all difficult with stock manifolds, though I'd port-match them just because I can't leave anything alone or pass up "free" power. You don't need a Holley or headers to hit your target; I've done it.
What's your budget for the motor? Do you want it to have nice street manners and/or relatively smooth idle?
The stroker deal will be less peaky at the same power level, since as a street motor what matters most is torque; if you need to buy all the parts anyway, it's a slam dunk. I'd go with the Stealths, with upgraded hardware and attention paid to the valve job & chasing threads. If you want to run 13/16-hex plugs, you need to open up the area where your plug socket interferes with the casting.

Posted By: gch

Re: Stock appearing 425hp 383 possible? - 10/13/12 07:56 PM

No matter what you decide the power you want lies in the head/headwork.With a set of good flowing heads you can easily hit that goal with a 383.
Any larger displacement will only make it easier.

Posted By: 70Cuda383

Re: Stock appearing 425hp 383 possible? - 10/14/12 01:06 PM

What kind of Hp are the FAST guys making with manifolds?

I also don't see any reason to NOT use a stroker. Total Hp may be the same, but with a stroker, you'll get that Hp at a much lower RPM and will be easier on the parts inside the engine

Posted By: YYZ

Re: Stock appearing 425hp 383 possible? - 10/14/12 01:23 PM

Quote:

What kind of Hp are the FAST guys making with manifolds?

I also don't see any reason to NOT use a stroker. Total Hp may be the same, but with a stroker, you'll get that Hp at a much lower RPM and will be easier on the parts inside the engine

I agree.

3.75-3.91 stroke won't hurt the budget and won't cause extreme stresses on the bottom end.

Plus the final displacements with either of those will be near enough to 440CI, which is what the stock heads were designed for.

Going to 484 or 500CI IMHO is a whole different ballgame....

Posted By: greenmcode

Re: Stock appearing 425hp 383 possible? - 10/14/12 01:51 PM

Quote:

What kind of Hp are the FAST guys making with manifolds?

I run a stock stroke 440-6 in my A12 runner...The reason i went
that rout than a stroker is the car is a real m code and wanted
to keep the originality of the car...I was asked why, Its cheaper
to buy a stroker kit and so on.. As for the H.P. it was never
dyno, The car is 3920 11.65 at 117.60 175 60' on bias..
12 to 1 comp.
hyd flat tappet..

I would build what you want.. Can you get 425 hp out of a stock
stroke 383? I would think so..

Posted By: Big Squeeze

Re: Stock appearing 425hp 383 possible? - 10/14/12 03:27 PM

Quote:

. As for the H.P. it was never
dyno, The car is 3920 11.65 at 117.60 175 60' on bias..
12 to 1 comp.

Your car is making about 516hp....Question is, how much does a motor like that cost???

Posted By: Mr.Yuck

Re: Stock appearing 425hp 383 possible? - 10/14/12 03:37 PM

I'd think it be very easy. 383 or 400 w/ a 440 crank, 10:1, ported stealth heads, cleaned up mani's, DP4B, custom hydro cam, 750HP carb, good ignitions system and you should have an easy 425.

Posted By: dannysbee

Re: Stock appearing 425hp 383 possible? - 10/14/12 05:28 PM

Here is a rescipe for you. Not exactly what you asked for but very economical build with good results. 451- 400 block, 10.5 compression with KB reverse dome pistons .040 quench, pocket ported 452 heads with stock valves, Hughes 223-230 at 50 cam with 1.6 rockers, hp manifolds and ported cast iron intake with 440 avs. Best 1/8 mile pass was 7.77 at 87 mph in a 3860 lbs Super Bee, never dynoed it but I feel it was close to your goal and had a very stock idle

Posted By: HPMike

Re: Stock appearing 425hp 383 possible? - 10/14/12 05:32 PM

I'd love to see dyno sheets of all these pump gas, stock stroke, iron headed 383's, with stock logs making honest 425+ HP. Easy? I dont think so...

MB

Posted By: greenmcode

Re: Stock appearing 425hp 383 possible? - 10/14/12 06:41 PM

Quote:

Quote:

. As for the H.P. it was never
dyno, The car is 3920 11.65 at 117.60 175 60' on bias..
12 to 1 comp.

Your car is making about 516hp....Question is, how much does a motor like that cost???

BIG BUCKS!!!!

Posted By: dannysbee

Re: Stock appearing 425hp 383 possible? - 10/14/12 09:17 PM

Quote:

I'd love to see dyno sheets of all these pump gas, stock stroke, iron headed 383's, with stock logs making honest 425+ HP. Easy? I dont think so...

MB

The combo I posted was never dynoed but it would run 110- 111 in the quarter and at 3860 I am pretty sure it was in the 425 ball park.

Of coarse at 451" it was stock 440 stroke. This was a low budget build with good machine work. Car was street driven and made 100's of pass shifted at 5500. I would not hesitate to build another one just like it.

Posted By: dulcich

Re: Stock appearing 425hp 383 possible? - 10/14/12 09:30 PM

[quote}
But Mike , there is a mopar muscle article from back in the early part of the last decade that made it look easy as pie ....

...

I know it is not an easy feat , though many think it is .

Well, John, I guess if you are referring to this story your memory might be failing you. I don't see 425 hp with stock exhaust manifolds and intake manifold.

383; RESTO TO RAD
Building Mopar�s Underrated Big Block
Text and Photography by Steve Dulcich

What�s not to like about the 383? It seems that these engines have fallen somewhat out of favor in recent years as attention has turned to big blocks of ever increasing cubic inches. For a moderate investment, a 383 can be built into a sweet high-revving powerhouse. Study the 383�s numbers compared to the popular engines of the competition. The 383 carries a bore and stroke of 4.25�x3.375�, while the 396 Rat had a embarrassingly undersized bore of 4.094�, and a 3.766� stroke - as long of an arm as a 440. At the Ford camp, the 390 was even worse, with a bore only slightly bigger than a 340 at 4.050�, and again a 440ish stroke length of 3.780�. The 383 was a thoroughbred by comparison to the competition�s similarly-sized big blocks. In fact, the FE Ford fan�s coveted 427 block had less bore diameter than the dirt-common Mopar 383. Even the Chevy guys� big guns, the 427 rat and the 454 had bores no bigger than Chrysler�s 383. You won�t see Ford or Chevy fans passing up 427 FE's or 427 and 454 Rats, but we tend to walk by those 383s with nary a second look. Why?

We decided to explore the 383�s hidden potential. Anyone who remembers the 383 equipped musclecars knows that these engines can run. Garden variety 383 RoadRunners, Superbees, Challengers, �Cudas and A-bodies vastly outnumbered the more exotic Hemi and Sixpack cars back in the day, and these 383 cars contributed far more to the musclecar mystique and legend than they are given credit for today. We decided to put a 383 together to blueprint-stock specs, and see just how much power a stock 383 put out. We also know that the 383 was one of the most modified engine ever installed in performance cars, responding eagerly to basic bolt-on speed equipment. To tap into that potential, we�ll baseline the stock engine on the dyno, and then use some of today�s best performance hardware, taking our 383 from resto-stock to racy-rad.

THE BUILD
Our goal was to start with a stock-spec 383, built to match the 383 Magnum engines of yesterday. As we started with a well-worn core, the crank was already ground down to the minimum, and the block was already bored .030�. Taking the block out to .060�-over didn�t have us worried, but we were still left with finding a crank. We tapped into PAW�s extensive catalogue for their SuperStock master kit, which includes a crankshaft, rods, pistons, rings, bearings, gasket, oil pump, timing set, cam, and lifters � basically everything we would need to make our 383 as good as new. A few upgrades we made to the base kit, including custom balancing, moly rings, chrome moly rod bolts, and a high volume oil pump. These low-cost options on the PAW kit were well worth the price for the sake of performance and reliability.

Also on our list of upgrades was a set of KB-162 Hypereutectic pistons. These pistons are designed to give approximately the stock compression ratio, but have generous valve notches allowing us to move to a fairly aggressive camshaft later on. For the baseline, a Resto-spec Mopar Performance �RoadRunner� cam and lifter package were specified as an extra cost option, since we were looking to duplicate a factory 383 Magnum for our initial configuration. We were also short an oil pan, so a PAW unpainted steel replacement sump was ordered, along with a dipstick and tube kit. Even though we were starting with little more than the original block, the PAW kit made building a balanced and blueprinted 383 bottom-end surprisingly affordable, and very easy.

With the required parts in hand, all we had to contend with was the block machining. The block was handed off to Jim Grubbs Motorsports, in Valencia, CA. Jim�s crew cleaned our 383 block, bored the block, and honed it with torque plates to fanatical precision. The block was decked squared to the crank centerline using a BHJ indexing fixture on Grubbs� Rottler mill. A cut of .010� on our previously machine block gave us a zero deck height with our KB Hypereutectic pistons. That�s all the machining we needed for this project. We already had a set of fresh #906 cylinder heads, rebuilt to stock specs with the original 2.08/1.74� valves, which we had previously rebuilt ourselves with new guides and a Serdi valvejob.

Using the PAW kit and Grubbs-machined block we had all the components ready to put together our 383 in a remarkably short time. Since this was to be a basic stock rebuild, the actual assembly was very quick, simple and trouble-free. The stock #906 heads were milled .020� to compensate for the thicker replacement head gasket, reducing the chamber volume from the stock 87 to 83cc. The deep valve notches in the KB pistons (6cc) coupled with the 84cc open chamber heads gave us a compression ratio of 9.2:1. Overall it was a 383 just like Chrysler used to build. We gathered up an original 383 Magnum AVS carb, the correct #666 iron intake manifold, a real set of factory high performance exhaust manifolds. Overlooking the Mopar electronic ignition distributor, installed more for reliability than performance, our 383 on the engine stand was like artifact from the past. We had only one question � How much power would it make?

TRUTH OR LIES
Much has been said of the horsepower numbers game in the musclecar era. Sometimes the claim is made that the gross ratings were wildly optimistic. In some cases, the assertion is that certain engines were �Seriously under-rated�. We�ve been here before, and generally found that Chrysler was fairly accurate in its ratings compared to dyno numbers we�ve seen on stock engines. We dutifully loaded our 383 onto the SuperFlow dyno at Westech to see how many of the factory-rated 335 horses were real or imagined. The 383 sparked instantly to life, and we were struck by how mellow it sounded through the factory manifolds. After the customary break-in cycle, we let the 383 fly. The readout at the end of the pull showed 335.2 HP @ 5000 RPM, and 392 Ft lbs @ 3600. 335 HP indeed. We adjusted the timing from 35 degrees total to 38, and ran a couple of back-up pulls. The 383 responded with 338 HP @ 5000, and 394.6 ft lbs @ 3600 RPM. No, Ma Mopar wasn�t lying when she hung the numbers on the high performance 383.

POWER MODS
While 338 HP for any stock engine is very respectable, we really wanted to explore the power producing potential of the 383. This time around, we would keep the basic 383 long-block package stock, but shake out some of the power hidden within with basic bolt-ons. Our first target was the same chosen by countless thousands of 383 owners over the years, adding a set of tube headers. We pulled down the magnum manifolds and replaced them with a set of Hooker #5101-1 headers. Was much to be gained over the sleek high performance manifolds? The headers added a solid 15-25 ft lbs of torque across the full range of our test RPMs. That�s added power you�d definitely feel.

Next, we set our sights on the original AVS carb. We went straight to kill here with an 850 Demon carb. The 850 may be considered too much at this mild state of tune, but with our subsequent modification plan, it would be just enough. The added airflow was a definite improvement, with the 383 now edging up to 367.2 @ 5100 RPM, and 434 ft-lbs @ 3600. Contrary to conventional wisdom, we found the big carb actually added substantially to torque in the lower to midrange, up as much as 25 ft lbs. The top-end numbers were also up, the gains weren�t as dramatic. We knew exactly what was holding the 383 back at higher Rpm�s, that big heavy chunk of cast iron sitting under the carb.

To unlock the 383s breathing efficiency, our next mod was to swap the stock iron intake for Mopar Performance M-1 single plane manifold. With the intake change, the visual character of our 383 was transformed. It was finally looking like a performance mill. Our next pull showed that looks were more than skin deep, with the dyno numbers now catapulting to 406 HP @ 5400 RPM, and 433 ft-lbs @ 4000. True to form, we lost a handful of ft-lbs down low in going from a dual plane to a single plane, but we gained huge up top. Yes, 383s can make power, and make it cheap. We had a rebuilt stock engine, with headers, a carb, and intake, and were churning better than 400 HP. We were impressed.

Our final mod, not surprisingly, was a good old-fashioned cam swap. There was, however, nothing old-fashioned about the grind. Competition Cams has recently introduced a line of Mopar specific high-lift camshafts. We were eager to try one of the new Comp bumpsticks, and ordered up an XE285HL-10. This is a fairly serious hydraulic profile, rated at 285/297 degrees gross duration, and specing out at 241/247 degrees duration @ .050�, with .545�/.545� lift, on a 110 degree lobe separation. The cam was degreed-in at four degrees advance, and topped with a set of matching Comp lifters. We upped the valvesprings at the same time to Comp�s # 924 dual-spring assemblies, since the high-lift cam requires much more spring than the stock 383 cam. We were still budget-conscious with this engine, and elected to retain the stock 383�s valvetrain.

Back up and running with the big stick, the 383 had a much weightier thump. With the stock heads the cam would likely not realize its full potential with our present combo, but we still expected a gain, and expected to pull higher RPMs. With that in mind, the dyno controls were reset to 6200 RPM, and we opened the 383 up once again. It pulled cleanly through the revs, and we now had a 455 HP 383. Peak power was actually 454.9HP @ 6000 RPM, and 456.6 ft lbs @ 4800. With the big cam we lost 5-10 HP at the bottom of our test range, but from the midrange up the Comp stick just pulled away like a freight train, posting a gain of nearly 50 HP. The useable RPM range of the engine was extended by better than 500 RPM in the bargain. We have to say we were impressed with the 383. Stock other than headers, cam, intake, and carb, we were solidly over 450 HP. That�s dollar value per horsepower.

DYNO RESULTS
HORSEPOWER
SUPERFLOW 901 DYNO
TESTED AT WESTECH PERFORMANCE GROUP

TORQUE
RPM STK HDRS CARB INTKE CAM
3000 382.7 406.3 427.1 405.5 394.2
3200 388.1 406.6 422.6 410.9 400.0
3400 388.3 412.6 431.9 421.2 414.7
3600 394.6 411.2 433.7 426.1 431.5
3800 392.4 408.3 430.8 430.0 435.5
4000 387.2 401.3 424.6 433.0 446.5
4200 377.8 396.2 416.4 430.1 451.5
4400 371.4 390.2 409.7 430.1 451.8
4600 367.8 384.6 402.0 427.8 454.2
4800 361.6 379.5 398.5 424.3 456.6
5000 355.1 373.4 385.6 421.3 450.3
5200 337.2 357.8 368.1 407.7 449.1
5400 322.8 348.5 351.4 395.1 435.8
5600 xxxxx xxxxx xxxxx xxxxx 417.0
5800 xxxxx xxxxx xxxxx xxxxx 407.6
6000 xxxxx xxxxx xxxxx xxxxx 398.2

HORSEPOWER
RPM STK HDRS CARB INTKE CAM
3000 218.6 232.1 244.0 231.6 225.2
3200 236.5 247.7 257.5 250.3 243.7
3400 251.4 267.1 279.6 272.7 268.5
3600 270.5 281.9 297.3 292.1 295.8
3800 283.9 295.4 311.7 311.1 315.1
4000 294.9 305.6 323.4 329.8 340.0
4200 302.1 316.8 333.0 343.9 361.1
4400 311.1 326.9 343.2 360.4 378.5
4600 322.2 336.8 352.1 374.7 397.8
4800 330.5 346.8 364.2 387.8 417.3
5000 338.0 355.5 367.1 401.1 428.7
5200 333.9 354.2 364.5 403.7 444.6
5400 331.9 358.3 361.3 406.3 448.1
5600 xxxxx xxxxx xxxxx xxxxx 444.6
5800 xxxxx xxxxx xxxxx xxxxx 450.1
6000 xxxxx xxxxx xxxxx xxxxx 454.9

Posted By: HPMike

Re: Stock appearing 425hp 383 possible? - 10/15/12 12:56 AM

Quote:

Quote:

I'd love to see dyno sheets of all these pump gas, stock stroke, iron headed 383's, with stock logs making honest 425+ HP. Easy? I dont think so...

MB

The combo I posted was never dynoed but it would run 110- 111 in the quarter and at 3860 I am pretty sure it was in the 425 ball park.

Of coarse at 451" it was stock 440 stroke. This was a low budget build with good machine work. Car was street driven and made 100's of pass shifted at 5500. I would not hesitate to build another one just like it.

With all due respect, its not a 383...Sounds like a nice little combo, though...

All I am saying is that if you read some of the replies in this thread you would think that making 425+ hp out of a stockish, pump gas 383 with manifolds is childs play..

I say no way...

MB

Posted By: JohnRR

Re: Stock appearing 425hp 383 possible? - 10/15/12 08:23 AM

Quote:

With all due respect, its not a 383...Sounds like a nice little combo, though...

MB

What's 67 cubes between friends ???

Posted By: JohnRR

Re: Stock appearing 425hp 383 possible? - 10/15/12 08:27 AM

Quote:

Well, John, I guess if you are referring to this story your memory might be failing you. I don't see 425 hp with stock exhaust manifolds and intake manifold.

Yes that would be it Steve , I guess that infamous west coast dyno wasn't as happy as usual on that day ...

Lots of good work in that build, keep up the good work.

Posted By: deaks

Re: Stock appearing 425hp 383 possible? - 10/15/12 08:34 AM

Quote:

Quote:

Quote:

I'd love to see dyno sheets of all these pump gas, stock stroke, iron headed 383's, with stock logs making honest 425+ HP. Easy? I dont think so...

MB

With all due respect, its not a 383...Sounds like a nice little combo, though...

All I am saying is that if you read some of the replies in this thread you would think that making 425+ hp out of a stockish, pump gas 383 with manifolds is childs play..

I say no way...

MB

I agree, Dwayne porter aside. My friend ran a full weight satellite + 260# driver, it had the old TRW domes, ported 906 heads, headers, rpm intake, 750 D/P, .255/265 at .050 crower solid cam, 3500 converter and ran 12.4 at 110 with the exhaust uncorked. According to the wallace calc, his speed is around 420 HP but his et is under 400.
Mick

Posted By: Slant6pak

Re: Stock appearing 425hp 383 possible? - 10/17/12 02:58 AM

Thank you to all who have replied.

Below is the reason I don't want to build a stoker. Again I don't even have an engine right now... if I wanted more cubes I could simply locate another 440....

I want a faster revving engine paired to a nice manual trans that pulls strongly through the gears. My hp goal is general, if I make awesome if I get close that is fine as well. I'd be content with a stock 383 if I didn't feel I could improve its power for not much more money that a stock type rebuild and head work.

I have had my fair share of torque monsters... I'm tired of replacing tires.

Quote:

[quote}

What�s not to like about the 383? It seems that these engines have fallen somewhat out of favor in recent years as attention has turned to big blocks of ever increasing cubic inches. For a moderate investment, a 383 can be built into a sweet high-revving powerhouse. Study the 383�s numbers compared to the popular engines of the competition. The 383 carries a bore and stroke of 4.25�x3.375�, while the 396 Rat had a embarrassingly undersized bore of 4.094�, and a 3.766� stroke - as long of an arm as a 440. At the Ford camp, the 390 was even worse, with a bore only slightly bigger than a 340 at 4.050�, and again a 440ish stroke length of 3.780�. The 383 was a thoroughbred by comparison to the competition�s similarly-sized big blocks. In fact, the FE Ford fan�s coveted 427 block had less bore diameter than the dirt-common Mopar 383. Even the Chevy guys� big guns, the 427 rat and the 454 had bores no bigger than Chrysler�s 383. You won�t see Ford or Chevy fans passing up 427 FE's or 427 and 454 Rats, but we tend to walk by those 383s with nary a second look. Why?

We decided to explore the 383�s hidden potential. Anyone who remembers the 383 equipped musclecars knows that these engines can run. Garden variety 383 RoadRunners, Superbees, Challengers, �Cudas and A-bodies vastly outnumbered the more exotic Hemi and Sixpack cars back in the day, and these 383 cars contributed far more to the musclecar mystique and legend than they are given credit for today.

Posted By: gch

Re: Stock appearing 425hp 383 possible? - 10/18/12 01:31 AM

Quote:

No matter what you decide the power you want lies in the head/headwork.With a set of good flowing heads you can easily hit that goal with a 383.
Any larger displacement will only make it easier.

Just have a cam ground for manifolds and the DP4B intake will be a big help.Should be fun and quick enough.

Posted By: Winchester 73

Re: Stock appearing 425hp 383 possible? - 10/18/12 02:22 AM

425 hp 383 possible?i guess so,every chevy one ever bolted together makes at least 600 so

Posted By: patrick

Re: Stock appearing 425hp 383 possible? - 10/18/12 02:37 PM

andyF had built stock stroke 400 build that IIRC made 580HP through headers...

IIRC it had ported eddies (paint 'em and most won't notice), an eddie RPM, 800CFM eddie carb and a smallish solid roller cam, IIRC.

Posted By: patrick

Re: Stock appearing 425hp 383 possible? - 10/18/12 02:38 PM

Quote:

Quote:

Well, John, I guess if you are referring to this story your memory might be failing you. I don't see 425 hp with stock exhaust manifolds and intake manifold.

Yes that would be it Steve , I guess that infamous west coast dyno wasn't as happy as usual on that day ...

Lots of good work in that build, keep up the good work.

note, first mod was headers

Posted By: dogdays

Re: Stock appearing 425hp 383 possible? - 10/18/12 04:07 PM

Sub note: Torque increased everywhere., starting at the lowest testing point, 3000 rpm.

Headers do more work than just reducing flow restriction. The "tuning effect" of long tube headers cannot be denied.

Here are two more thoughts:
1. If I were going to do a story on a 383 with a HE285XL cam I'd start the dyno at 3000 rpm, too. That's quite a big cam for the engine, too big for the street.

2. AndyF had the best results using the MP .528 cam with HP manifolds. Assuming the cam events were the factors resulting in success, would it make sense to have a custom cam ground using those same events but with higher lift? Much work has been done on optimizing cam lobes since the .528 was designed.

R.

Posted By: patrick

Re: Stock appearing 425hp 383 possible? - 10/18/12 06:42 PM

Quote:

2. AndyF had the best results using the MP .528 cam with HP manifolds. Assuming the cam events were the factors resulting in success, would it make sense to have a custom cam ground using those same events but with higher lift? Much work has been done on optimizing cam lobes since the .528 was designed.

R.

might be easier to use 1.6-1.7 ratio rockers, or find a similar .050 duration roller lobe, which will have a lot more lift...

Posted By: AndyF

Re: Stock appearing 425hp 383 possible? - 10/18/12 07:15 PM

The engine that I used the .528 solid on was a 470 inch low deck stroker. I did use HP manifolds on that engine and it did make around 550 hp on the dyno. It also made 475 rwhp on the chassis dyno. But I'm sure the extra 80 cubic inches helped a bunch.

Posted By: AndyF

Re: Stock appearing 425hp 383 possible? - 10/18/12 07:20 PM

Quote:

andyF had built stock stroke 400 build that IIRC made 580HP through headers...

IIRC it had ported eddies (paint 'em and most won't notice), an eddie RPM, 800CFM eddie carb and a smallish solid roller cam, IIRC.

That is all true, but that engine was also more of a race motor than a street motor. We had as much compression as we could fit into the combustion chambers. I think that engine was over 12:1. That was a killer motor. It went into a '72 Duster and the guy had a lot of fun on the street as well as the track.

Posted By: fast68plymouth

Re: Stock appearing 425hp 383 possible? - 10/28/12 01:23 AM

Quote:

An honest 425 horse on a legit dyno with a 10:1 383, exhaust manifolds, iron heads, and that intake is no easy feat...Not saying it can't be done, but it won't be like falling off a log.

MB

its not like falling off a log......but is definately doable.

my 383.....
.030 over, TRW's, 9.8 actual CR, RPM intake, pocket ported 346's(about 260cfm), Holley 750 carb, HP manifolds, custom solid lifter cam(.550 lift)........made right about 420hp at 6300rpm on pump gas.
in retrospect, i think the cam had a tad too much duration as the TQ number was only a bit over 420 ft/lbs.

i think a little smaller cam would have boosted the tq numbers in the mid-range.....and may have carried that up into the upper rpms well enough to yield a few more HP as well.

Attached picture 7437728-PRH383-street.gif

Attached picture 7437728-PRH383-street.gif

Posted By: az426hemi

Re: Stock appearing 425hp 383 possible? - 10/30/12 09:16 PM

Quote:

Thank you to all who have replied. Below is the reason I don't want to build a stoker. Again I don't even have an engine right now... if I wanted more cubes I could simply locate another 440.... I want a faster revving engine paired to a nice manual trans that pulls strongly through the gears. My hp goal is general, if I make awesome if I get close that is fine as well. I'd be content with a stock 383 if I didn't feel I could improve its power for not much more money that a stock type rebuild and head work. I have had my fair share of torque monsters... I'm tired of replacing tires.
Quote:

[quote} What�s not to like about the 383? It seems that these engines have fallen somewhat out of favor in recent years as attention has turned to big blocks of ever increasing cubic inches. For a moderate investment, a 383 can be built into a sweet high-revving powerhouse. Study the 383�s numbers compared to the popular engines of the competition. The 383 carries a bore and stroke of 4.25�x3.375�, while the 396 Rat had a embarrassingly undersized bore of 4.094�, and a 3.766� stroke - as long of an arm as a 440. At the Ford camp, the 390 was even worse, with a bore only slightly bigger than a 340 at 4.050�, and again a 440ish stroke length of 3.780�. The 383 was a thoroughbred by comparison to the competition�s similarly-sized big blocks. In fact, the FE Ford fan�s coveted 427 block had less bore diameter than the dirt-common Mopar 383. Even the Chevy guys� big guns, the 427 rat and the 454 had bores no bigger than Chrysler�s 383. You won�t see Ford or Chevy fans passing up 427 FE's or 427 and 454 Rats, but we tend to walk by those 383s with nary a second look. Why? We decided to explore the 383�s hidden potential. Anyone who remembers the 383 equipped musclecars knows that these engines can run. Garden variety 383 RoadRunners, Superbees, Challengers, �Cudas and A-bodies vastly outnumbered the more exotic Hemi and Sixpack cars back in the day, and these 383 cars contributed far more to the musclecar mystique and legend than they are given credit for today.

I too wanted to build a high revving, solid lifter 383 4 speed car. The best engine that I built almost 40 years ago after high school was a 396/375hp 55 Chev. Sweet combo. I wanted to duplicate that performance with a 383. So my current project is a 64 Dart with a 383 4 speed and a Dana 60.

The engine is about to be assembled. It has KB400 10.5 pistons, H beam rods, a main cap girdle, Stealth heads with Stage 1 porting by Muscle Motors, .528 cam, RPM intake, Bigs 750 Holley, and HP manifolds.

Can't wait!!

Mike

Stock appearing 425hp 383 possible?