Thoughts on mild 383

Hi everybody!
Looking for input on my matching 71 Charger Super Bee engine.
Let's start with to say that I'm somewhat on a budget. Plus I like doing the job myself so the engine will not leave my workshop until test drive.
I like being cheap but I want things to be properly done so I can rely on my engines when they are finished.
I have other projects I need to finish before this one so I'm just setting up the plan and gathering parts right now. Car is at my body guy's place and I hopefully will get it painted so I can have it finished by next summer.

Goal is to get a strong torque engine so I can keep the original converter and 3.23's. Lots of power directly from bottom makes cars fun. Power on tap is beautiful.

Talking about torque converter, I do hope it still has the correct HP 10 3/4"! It's still in the car so can't check for the moment, just came to think of it. IIRC that converter stalls around 2,500?
Well, with a stall at that level I guess it's no longer need for a real torque engine. Please, keep on reading and I'll give you the basis for my build.
Need vacuum for the power brakes but that should not be an issue with the characteristics I'm looking for.

I will port the 906's using the old templates. Cleaning up the bowls, straightening and cleaning up a little. Do a basic 3-angle valve job. Mill them if necessary to achieve correct compression ratio.
The cylinder bores will clean up with honing. Maybe not 100% perfectly clean up but good enough.
Reuse the original pistons but swap them side to side for a little more thump.
Use a windage tray and a larger pan never hurts even if this engine rarely will see rpm's over 4,500.
Have a nice pair of HP exhaust manifolds. Will build a full exhaust 2.5" H-pipe of mandrel bent aluminized tubes. Don't know what mufflers to use. Think Flowmasters are too noisy, even the 50's.
Still looking for a CH4B intake. From what I've heard and read that could be the optimal intake for a 383 like this.
Think I have an old good points distributor that I can put Petronix on. I don't trust the MP stuff anymore. Limit mechanical advance, lighter springs.
A spreadbore carb. Haven't looked for what I have. A 600 would do the job. Need to find an oval base 4bbl air cleaner to a decent price since it has the Air Grabber hood.
Will rebuild the 727 and put in a semi manual valve body. Car is column shifted.

Now the most interesting part. Cam selection.
My friend has a set original 440 adjustable rockers. I think I can make him sell them to me. If so I could go mechanical cam. If not I'll stay with stamped steelies.
Would a mechanical cam have big advantage over a hydraulic in an engine as described, or will it only make difference at higher rpm's?
What cam would you use based on the basis above?

Finally, I'm aware of 383's rod ratio and bore to stroke ratio. A high revving engine, not a torque monster. I know, but as I said before, I want a snappy, stong-off-the-bottom, daily driver but tire melting 383".
My hope is that it will run low 8's on 275 street tires in an otherwise original heavy 71 Super Bee... We'll see if that happens
To stroke it would make my goal easier but I'm not willing to spend that amount of money that comes with building a stroker. Especially not at this point. I am in Sweden and shipping parts from the US is a PITA these days. Been waiting for a box with parts shipped with USPS since mid May. It's stuck in Miami...

I'd be grateful for your input. Thanks in advance!

CH4B is a square-bore intake; spreadbore carbs like a Thermoquad won't fit without an adapter, though you MAY be able to modify the intake.
Back in the day, we'd use a 440 AVS to pick up some CFM; now, I prefer the Eddy AVS2. I do like the T-quads though.
Cam: you can throw lift at it, but too much duration will make for lazy low-RPM response.
I'd probably keep duration under 230 @ .050 but look for around .500 lift, favoring the exhaust side for what you're doing.
I wouldn't worry about mech/hyd lifters, but I would get the Johnson or similar improved-oiling ones.
A Street Hemi pan is pretty stealthy but an additional quart capacity, and a Milodon or MP tray with the drains opened up a bit works.
I've had a 383 like the above that would indeed blaze the tires with 3.23s & stock converter, stock manifolds, cleaned up stock heads, 9.5:1 ('68 Road Runner).
Looked totally original.

Streetmaster is a good spreadbore intake.

CH4B does not fit on a 383. It is made to fit on the RB engines(413, 426,440). You need to find a DP4B.

Not judging your desire for a spreadbore carb, but if you do go that route, don't use the Holley Street Dominator intake, it is a low end killer.

And a Performer intake is pretty much the same as the DP4B, but will accept a Thermoquad or other spreadbore carb. Worth considering in my opinion.

The 383 is already torque challenged down low. Don't put a single plane on it

A mechanical cam is the only cam I'd put in a 383 application if you want to mazimize street friendly power. Unless you really don't care about power and performance, and only low end torque put some tiny cam in it and go ahead and keep it hydraulic.

I don’t agree with that. A street dominator is a great intake for a 383. Hood clearance is good. Need to run a 750 carb on it, just not a 1407 eddy. He also needs to make sure the compression is good, even if it means custom pistons, which last I knew it required if you wanted a sharp setup on a 383.

Aha, took for granted CH4B (or actually DP4B as someone pointed out) would fit a spreadbore carb. I will look deeper into intakes.
I want small primaries to get high velocity speed in the range I mostly will use the engine. I also like Thermoquads but they are a hassle to adjust correctly... I have good experience of the Street Demon. 625 cfm will be more than enough but the design of the secondaries is similar to the TQ so they only give what the engine vacuum demands.
I have been looking around a little for cams. Just like you say I'm looking for high lift and low duration. Hughes has http://www.hughesengines.com/Index/...amp;level1=Q2Ftc2hhZnQ=&partid=30253 and they always state that their grinds are for Mopar .904 lifters. I have always been happy with their cams before.

A Performer is a good candidate. I will look around.
For sure, I will go for a dual plane. With a single plane I won't even get near my goals.

Explicate why a mechanical cam would perform better in the lower rpm range. I have honestly never digged into that field. I have used mech cams in high revving street/strip engines but not in something like this.

Street Dominators are great intakes for making power. No doubt, I have been happy with them on 440's.
But with a single plane I'm giving up the rpm range I'm building the engine for. Need long runners for the lower rpm's.

4000+lb car, automatic, 3.23 rear, big tires, small engine + single plane intake and larger hydraulic cam = disappointment. piston/head combo-compression ratio/cylinder pressure are big factors in choosing the right parts for a 383, or any other engine for that matter. big ain't better when it comes to 383's.

If it were me, I'd call summit and buy the 465/488 cam, try and find a used DP4B or like intake, headers, clean the heads up as best you can and use a Holley 750. As long as the engine is out you should at least go to a 2800 stall. It would really wake the thing up.

It’s not like other single planes. Low end grunt is there. They work well on a mild 383. Guys who haven’t used them just lump them in with the race stuff. I’ve had them on a 383, 400, and a 440. All street cars with 3.23 gears. Most guys haven’t used one at all and just say “it’s a single plane, can’t do that.”

My only personal experience with the SD was on a 440 with a 10 inch 3500 converter. It worked well , but the old Torker I had on it before 60fted a tiny bit better. SD was about 1 mph faster in the 1/4 than the Torker for me. I wouldn't want to use a SD or any other single plane on a 383 with a low stall converter. The SD in this particular test had a weak low end compared to any of the dual planes : https://www.hotrod.com/articles/hrdp-0712-mopar-intake-manifold-comparo/

I was going to reference that shoot out too. Like 21 hp less with the SD than the DP4B at 3000 rpm. And average 9 hp less below 4500 rpm. My 383 car was a touch slower with the SD than a Performer on a mild ( high 12s) application. Could feel the difference cruising around town too.. Finally, even on my 500 motor dyno testing 3 intakes, the SD was noticably weaker below 4000 than the two dual planes tested. That surprised me on a 500 in motor.

I knew the hr article would come up. Here is a random sampler of what they found. The differences are so little it’s unlikely to be noticed driving. The peak numbers are intriguing to look at, but who knows why those are what they are when the averages look like this. Finding a deal on a manifold would be a way to free up budget for other things than to get caught up in absolutes like “it has to be this one, can’t be this one.” Likewise hood clearance is a crucial factor. There are inches of difference between some of those manifolds.

Average 2,500-4,500: 429 lb-ft, 289 hp
Average 4,500-6,000: 419 lb-ft, 417 hp
Average 2,500-6,000: 424 lb-ft, 344 hp

Average 2,500-4,500: 414 lb-ft, 280 hp
Average 4,500-6,000: 432 lb-ft, 430 hp
Average 2,500-6,000: 421 lb-ft, 344 hp

Average 2,500-4,500: 427 lb-ft, 288 hp
Average 4,500-6,000: 415 lb-ft, 413 hp
Average 2,500-6,000: 422 lb-ft, 341 hp

Average 2,500-4,500: 421 lb-ft, 284 hp
Average 4,500-6,000: 430 lb-ft, 427 hp
Average 2,500-6,000: 424 lb-ft, 345 hp

Average 2,500-4,500: 424 lb-ft, 287 hp
Average 4,500-6,000: 428 lb-ft, 426 hp
Average 2,500-6,000: 425 lb-ft, 346 hp

Average 2,500-4,500: 423 lb-ft, 286 hp
Average 4,500-6,000: 435 lb-ft, 433 hp
Average 2,500-6,000: 427 lb-ft, 348 hp

Random heights

front 311/42, rear 451/48
front 431/44, rear 531/44
front 311/44, rear 411/48
front 331/48, rear 411/44
front 351/48, rear 411/42
front 411/42, rear 511/42
front 351/48, rear 411/42

My numbers from the article are correct, are they not? Plus that was with a large solid FT cam and pretty decent compression ratio if I remember correctly, and it was still lower by 9 hp average below 4500 rpm.

I went and looked up my dyno data for my 500 in motor. From 3000 to 4000 rpm, the SD was down on average 20 lbft torque, and 12 hp. Down 26 lbft and 15 hp @ 3500. As would be expected, it did make a touch more peak hp, and carried it longer past peak.

I've been doing this a long time as well, and I have not come across what I would call any crediable evidence that supports the age old belief that the SD is just as good down low as a dual plane.

Me thinks your goal of running in the 8 with a 383 in your car are unobtainable
All kidding aside, that car is heavy and those motors are limited on how much cheap power you can make with them, been there done that(multiple times)
Can you find a usable 440 crankshaft? If so I would use it by turning down the mains to 383 size and have a set of pistons made for using the stock 440 rods in your 383 , you will have to do some work, grinding the edges, on the crankshaft counterweights to clear the main webbing but increasing the stroke to 3.750 in a low deck is a really good way to help on the low end torque.
Being in Sweden has to limit your ability and choices on parts for this project so I can feel your pain and frustrations good luck

I've done back to back comparisons, same car, same engine, same tires with OEM and SD intake. SD intake and 3.91's, barely spin tires on idle stomp. OEM intake and 3.23's, much more spin from idle stomp. That's proof positive of low end difference.

This was a basically stock magnum 383 spec motor with 268H cam and 906's with normal 3 angle VJ, headers, 750 holley, nothing fancy at all.

I think you my have missunderstood my point, but my my wording was poor as well.

In short, maximizing power (track performance), and low rpm torque (the low speed "feel" of the motor) is hard, paticularly with a 383. These things compete with one another in a 383 more so than 440s. You also made a statement about 4500 rpm, and not sure what to infer from that. A stock 383 is pretty happy at 5500.

Anyways, to have your cake and eat it too, you need to put a cam in it that moves the valves fast, but will still keep the valvetrain happy to 6000 rpm. The fast rate hydraulic cams (or lifters) usually struggle at higher rpm. A faster rate solid cam can do both. Also, loosening the valve lash will sharpen-up the low throttle response noticably on a 383. The faster you move the valves and slap the valvetrain around, the harder it is on parts. It's always a compromise.

I've got that same basic set up. Runs strong and pulls hard. Good street set up with 3:23's and a TCI Breakaway converter.

i had the exact same experience working on two 383's. the one 383 car with the 3.91's and single plane was a total turd. the stock 3.23 geared 383 would have clobbered the other in a 1/4 mile.

with all things equal a solid cam is more flexible and will do everything a hydraulic will do and more. i'm with bsb67 on this one.

This got off into the weeds pretty quickly. If you are really going to run a stock converter, stock ex. manifolds 3.23:1 gears in a 383, forget the single plane manifold. Build as much compression ratio as your budget allows, use a dual plane intake of your choice with a 650-750V.S. carb., and don't over cam it. I have run stock manifolded 383's in 2 different 4 door (66& 68) Newports. Both ran mid 15's at 90ish m.p.h. with less than 8:1 compression,2.76-3.23 gears & stock heads.. I used a cam dynamics 266 energizer(.440" 266 210@.050") and a Crower 260 H.D.P. ( .456"-477" 260-267 212-218@.050). I liked the energizer better as it had tighter lobe sep. and better low end.A 230@ .050 cam and a single plane will be a turd below 3000-3500 R.P.M.

We’ve reached absurdly here. Intake swap cost like 100 ft pounds off idle. Yeah or whatever. Dyno results right in this thread show a variation of about 3% one way or another in favor of one manifold or another at various rpms. But with a simple intake swap you guys killed off triple digits of power. That takes some skill.

I agree, we ended up far out in the weeds LOL
Yes, I'm really gonna do what I stated from beginning. Maybe not the DP4B since it's not for spreadbore, which I'm gonna use.
I have never even considered a single plane for this build. This engine will need long runners.

I'm going to keep the compression pump gas friendly. We can get 93.5 oct here in Sweden (<5% ethanol). Cylinder pressure around healthy 160-170 psi is what I'm aiming for, that will leave some margin.

What I asked for was camshaft input for this specific build.
My thoughts of a cam are duration around 220 and maybe a little more on exhaust, lift as much as .500 and LS around 110. Talking hydraulic flat tappet now. But what do I know? LOL
It would be interested in some input - what cam and why?

FWIW my buddy had a 68 Charger, 383 2bbl motor with over 150k on it. He used the Summit 465/488 cam, headers, DP4B, Demon carb, 2.5 exhaust, auto w/ a mild stall. He ran 13.90's shifting like grandma. He did have 3.55's I think.

I don't understand the infatuation with the DP4B over a Performer 383... maybe because its old & people don't like change.

A Performer 383 intake IS and updated DP4B casting flipped 180 degrees with more favorable features, like mounting the coil in the right spot, the ability to mount a spreadbore, and the option of hooking up the factory choke.

I mean, I think I can read, but maybe not. That article shows a 37lb-ft difference at 3000rpm between the SD and the performer. 38 to the Action Plus. If they had tested down lower then that gap would surely increase. It wouldn't take 100lb-ft to make the difference I observed and shared in this thread.
I appreciate your compliments as to my skill in things mechanical as well as reading ability.

I've been thinking of how I should put it to make you understand of how I see it.
If you'd had a chance to log the throttle position for a season on a street driven car (such as a 71 'Bee) I'd swear you never go WOT more than a few percent. Probably very very few.
The idle portion would be quite a big number, depending on the traffic situation at your location of course.
If I make a wild guess of the throttle opening you actually DRIVE your car I'd say it's mostly between idle and half throttle. At least that's how I drive my cars. Using a set of 275 BFG takes only a few minutes of pedaling! LOL

The engine I'm planning to build is for a driver.
Looking at dyno numbers are always fun, but I don't know anyone who puts his street car in gear, floors it from 2,500-3,000 and wait 'til the power ends. Well, if he goes to the track, but that's a completely different story.

A dyno can't give the information of how the engine works in a street car. How responsive it is, and what will happen if you give 3/4 throttle at 2,000 rpm's. A chassis dyno can do it better, but not fully.

I want my street driven 383 to be long lasting, ready for long trips on winding sideways or a trip to the town to lay out some smokescreens and no unburned fuel wiping off the oil film from the cylinder walls.
I want it to be snappy and happy, have muscle car characteristics with a bit lumpy idle and grunt from bottom so I don't have to wait for it to happen.

If it wouldn't have been a matching car I would have used the 67 440 I have sitting, or maybe built a 400 stroker. It would have made it easier to achieve my goals, but that's not an option now.
If I had too much money or lived in the US I would have considered building a stroker out of the matching block, but that's too risky with today's situation. Shipping overseas sucks these days...
As said before, a 383 is not the best start - but now it has to be a 383, and I will try to make the best of it.

I'm gonna try to use the parts I have and do it all by myself at home. Do it and build it someway I stated from the start. Be painstaking with the details, jetting and timing.
What I'm asking for is cam input from people who built something similar. Anyone?

Sincerely regards!

Solid flat tappet. Comp cam: XS268S. Pretty mild, and easy on parts.

This is an internet amatur's recommendation from a catelog. I would suggest calling a professional.

in terms of the cam i'd be looking for a mopar .528 cam, i always liked the torque the cam had down low and always liked the way it drove. i think in terms of bang for your buck you really cant beat it in a street car.

I have also been looking at that one, it's mechanical. Very close to Hughes SEH2024BL-11 but more duration and a little less lift. Plus I'm not sure Comp grind their Mopar cams for the larger .904 lifters...

something to think about on solid cams is their advertised duration ratings. you need to look at how much lobe lift the seat timing is rated at. using the xs268 as an example I believe it is rated at .015" lobe lift, but the recommended lash setting is .016". to get 268 degrees on the seat with a true 1.5 rocker you'll need .022" lash setting. .016" lash setting is going to get you 8-10 more degrees on the seat. will that kill off some low end torque?, probably. looking at the 270 solid it's rated at .015" lobe lift but has .022" lash setting. would the 270 be more versatile?, perhaps. either way look before you leap. what got me into looking at this stuff is I bought a solid cam that was "rated" at 280 degrees. what I didn't know at the time was the 280 was at .020" lobe lift, but recommended lash was .020". long story short is my 280 cam actually has 295 degrees running duration at recommended lash. the only saving grace is the solid tappet. 295 hydraulic degrees would have been miserable for what i'm doing.

I'm going to tell you that I have been told, and saw it on here also, that Hughes has Comp grind al their cams for them so that being said I'm sure that all the cams Cp sells are designed around the .904 lifter size

I wish I could tell you what cam was used in this 383 engine but I cannot. Most likely it was some stock replacement hydraulic cam. The engine was built in 2002 and had about 10 miles it.

However we did run it on our engine dyno today 7/31/2020.

Fired it up with the stock iron 4150 type dual plane intake with a casting number ending in 301 and then changed to a Holley Street Dominator. The carburetor used was a 1406 Edelbrock.

RPM......Iron 301 TQ/HP......Street Dominator TQ/HP

2500.....349/166..................308/147
2700.....343/176..................310/159
2900.....351/194..................330/182
3100.....364/215..................343/202
3300.....361/227..................349/219
3500.....356/237..................350/234
3700.....349/246..................350/246
3900.....338/251..................350/260
4100.....336/262..................351/274
4300.....325/266..................348/285
4500.....315/270..................344/295
4700.....312/279..................338/303
4900.....298/278..................328/306
5000.....284/276..................320/305

END TEST

Listen to this guy! Put a crank in it and enjoy the low end that it will provide! I have a 470" low deck with a mild solid roller cam. Idles nicely at 900 rpm, looks like a 383, rpms like a chain saw and pulls like a freight train!!

I've been thinking of how I should put it to make you understand of how I see it.
If you'd had a chance to log the throttle position for a season on a street driven car (such as a 71 'Bee) I'd swear you never go WOT more than a few percent. Probably very very few.
The idle portion would be quite a big number, depending on the traffic situation at your location of course.
If I make a wild guess of the throttle opening you actually DRIVE your car I'd say it's mostly between idle and half throttle. At least that's how I drive my cars. Using a set of 275 BFG takes only a few minutes of pedaling! LOL

The engine I'm planning to build is for a driver.
Looking at dyno numbers are always fun, but I don't know anyone who puts his street car in gear, floors it from 2,500-3,000 and wait 'til the power ends. Well, if he goes to the track, but that's a completely different story.

A dyno can't give the information of how the engine works in a street car. How responsive it is, and what will happen if you give 3/4 throttle at 2,000 rpm's. A chassis dyno can do it better, but not fully.

I want my street driven 383 to be long lasting, ready for long trips on winding sideways or a trip to the town to lay out some smokescreens and no unburned fuel wiping off the oil film from the cylinder walls.
I want it to be snappy and happy, have muscle car characteristics with a bit lumpy idle and grunt from bottom so I don't have to wait for it to happen.

If it wouldn't have been a matching car I would have used the 67 440 I have sitting, or maybe built a 400 stroker. It would have made it easier to achieve my goals, but that's not an option now.
If I had too much money or lived in the US I would have considered building a stroker out of the matching block, but that's too risky with today's situation. Shipping overseas sucks these days...
As said before, a 383 is not the best start - but now it has to be a 383, and I will try to make the best of it.

I'm gonna try to use the parts I have and do it all by myself at home. Do it and build it someway I stated from the start. Be painstaking with the details, jetting and timing.
What I'm asking for is cam input from people who built something similar. Anyone?

Very good you did that test! It proves what we already have guessed - in this particular case the SD intake will start walking away first after 3,700 rpm.
Dual planes will always beat single planes in the lower rpm's.
Single planes will always beat dual planes in pure power. But you will need revs to get it.
It is the Law Of Physics.

I have also heard so. That Hughes let someone else grind their cams is no surprise. You need to be effective and grind a lot of cams all day long to make money.

My question then would be if Comp really design their Mopar grinds to take advantage of the bigger lifters in a way that make the cams make more/better power?
Dave at Hughes claim they do so, and I'm willing to believe him. Hughes are Mopar only and can put all their effort in maximizing their cam grinds.
Do Comp have resources to put their best engineers to design cams for Mopars only?
Some time ago I tried to compare Comp to Hughes grinds. Not scientifically but as well as I could just studying duration, lift and LS. It always seems like Hughes have steeper ramps and that makes me suspicious.

You are absolutely correct. I agree in every way.
Comparing a hydraulic cam profile to a mechanical is like comparing apples to bananas.
My head went bananas and I lost it. In the middle of the banana field I started to think that the Hughes cam was mechanical.

Be careful. Because hydraulic cams are generally rated at 0.006" lobe lift, their actual seat timing is also different than advertised.

Two points: 1) you can do a reasonable on-paper comparison between solid and hydraulic cams, you just need to know what you are doing, and 2) a 0.004" lash change will change seat timing lot, and will be very noticeable in a 383 driving around town.

I just finished my 383 rebuild - my goals were a little different from yours but there are some similarities. My primary goal was to get the engine close to stock, so it has the stock crank, heads, valvetrain, intake manifold, exhaust manifolds, and carb. No porting/port matching was done. Engine is 30 over, combustion chambers are about 87-88ccs, head gaskets are stock steel shim (0.02 compressed), pistons are Speed Pro L2315NF30 and they sit 4 thousandths in the hole. Compression ratio is about 9.5:1.

For the cam I wanted something that was close to stock. I ended up going with a Mr. Sixpack cam and so far it seems to work well. Vacuum is 17" and it idles smooth at 700 RPM. I only have 300 miles on the engine, so a little more break-in to go. It's definitely faster than it was prior to rebuild, and it suits my goals for the car.

Sounds like a sweet motor
I'll try to get a little more punch out of mine without sacrificing bottom power

I believe a favorite of many years ago was the Crower 271 https://www.summitracing.com/parts/cro-32242 .Yours may benefit from a slightly smaller profile or different lobe separation.Call Duane at Porter Racing Heads or pm him here for a recommendation addressing your specific needs/specs.
^
fast68plymouth

Thanks, sent Duane a PM

Thanks Jim

so if the engine makes something like 25 more horsepower on the engine dyno at about 1000rpm higher then how much of that 25hp will be ate up thru the chassis to spin the drive train about 1000rpm higher to get the 25hp? just asking.

1000rpm higher...... than what?

Both of those tests have the engine making peak power within 200rpm of each other.

If you “assume” the power numbers lose 20% from the engine dyno to the chassis dyno, then looking at the numbers at 4700..... 279 vs 303....... 24hp on the engine dyno...... x .80 = 19.2hp at the wheels.

I think it’s pretty safe to assume anyone running around with a hot street 383 will be running it to at least 5000 during some wot blasts.

To me that test illustrates the classic hot rod part “trade off”.

The manifold gained about 20-25hp from 4300 up....... and the downside was the 20+ft/lb it lost from 3100 down.

Depending on exactly what you’re doing with the motor...... it’s either a win or a loss.

just asking.