I built this engine years ago to put in my mother's 68 road runner in place of the original 383. It has been on the stand for a long time as garage art. LOL
It has now been 10 years and I wanted to see what it makes for HP and torque. So, it went on the dyno yesterday.
The rotating assy is 440 Source, Ross pistons, the block zero decked, Edelbrock RPM heads were checked out and had some minor bowl work. Rockers are Comp Pro Magnums, Edelbrock Performer RPM intake, gasket matched . The Comp Cam XE282 S solid FT, Smith Bros. push rods.
The cam was from Dwayne Porter and specked for the 3.23 gear and original RR torque converter.
I chose a Quick fuel 780 SS carb with vac. secondaries .
I also took with me my Race Demon RS 1050 carb to test.
I calculated 10.73 -1 compression and ran the test on pump gas.
I really wasn't sure what to expect for output, and I think it did pretty well.
What would be decent HP and torque numbers for this mild build ?
I will post the results later.
Thanks,
Mark

just a wild guess here since I'm posting to say, I'm glad to see this here because I want a build a very similar motor. thanks for posting.

538hp @ 6200
568tq @ 4800

I had an engine like that in my Coronet for a few years. Nice engine combo that was easy to build and ran really strong. Mine made 550 hp on the engine dyno and 475 rwhp on the chassis dyno.

I guess it would help to post the cam specs.

244* intake 252* exh. @ .050"
.520 int .540 exh.
110 Lobe sep
Howard's EDM lifters

I ran a MP .528 solid in mine. I tried some slightly larger cams like you have but they didn't make anymore power in my engine. Looks like you have good dyno headers in the picture so that might help out a bit. I ran HP manifolds on my engine.

I'd be looking for "around" 540hp/560tq, based off what I've seen from similarly built 446's, and adjusting for the added cubes.

I was talking to a friend of mine while we were dynoing a 505 he built for a customer about how there can be a fairly noticeable difference in what the dyno sheet says depending on where you go.........for a host of different reasons.

He reminded me of a 2bbl circle track motor he had years ago that he had tested, completely unchanged, at 3 different shops.
The high to low spread was about 30hp......on a motor that barely made 300hp.

It was something like 285/300/315.

Edit- I see you'll be running an elec water pump..... So add a few for that.

I think a lot of the difference comes from how the exhaust is handled as well as how good the intake air quality is. Other things to look at would be the weather conditions between different shops.

I've found that our dyno over corrects on the correction factor so if I'm trying to do A-B testing I have to confine myself to testing days where the weather is the same. I usually only test if the correction factor is close to 1.00 since the bigger correction factors don't seem to be accurate.

I'm not sure if there is any difference in power between the different brands of dynos. Acceleration rate and inertia factor and stuff like that can make some small differences but I think exhaust is probably the biggest issue most shops have.

It has been years since I had an engine on this dyno, but it was not at all generous with the numbers on the two Hemi engines I put on it in the past. In fact I was really disappointed with the out come on both of those engines.
I hear what you guys are saying, and I am just going to post what I have. Maybe you can look at the information and share your observation of the data. I am glad to learn from your experience.
Andy, I have your book and read about your cam testing on the 470, with exhaust manifolds.
These dyno headers were 2" diam. and I am going to use 1 7/8" TTI headers.

Mark

You don't have a lot of duration, and are using the RPM intake so that should hold the HP back some but have some Great torque, IMO So, I will say about 535 HP and 565# of torque. Should be a great running engine with your gear and stock vert.

That cam seems to produce really strong flat torque curves and "overachieve" a little on HP. I think the guesses given so far, 530-540 HP and 560-570 ft lbs are right on. I've seen a few dyno results for stock stroke engines with this cam and they seem make about 520 HP and 540 ft lbs.

At first glance it looks a little small for a solid cam using the old rule of thumb of 6-8 degrees of the .050 number for a solid vs hydro. The lash on those XS lobes is tighter than alot of other cams though, so I think its a little deceiving.

I asked the shop owner for his estimate, as well as the dyno operator just for the fun of it. The shop owner said 550, the dyno operator guessed 550 to 570, based on similar sized BBC engines he had tested with "good" heads.
Here are the results.
First is Demon 1050
The second is the Quick fuel 780 carb.
Last is Demon 1050
Mark

Dang that thing is making alot of torque.

Man, Hard to believe it can make those kind of numbers with only a actual 238* of intake duration @ .050 with the lash considered in. But it makes torque down low and torque makes HP. The heads flow enough at those rpms to make those numbers possible, but just never seen that before with a combo like that. If those numbers can really be trusted of being real, you have one heell of a runner there.

Where any carb changes made during the session? The 780 is leaner than the 1050.

Yes the quick fuel was leaned out 2 numbers front and 4 on the rear. I would have to do some checking to see the actual sizes.

About all I can come up with is......
Great call on the cam choice

Nice combo Mark.. Lets see some pics of mom's runner .. Larry

You got it Larry !

I am inclined to agree Dwayne.

Thanks,
Mark

Bad ass RR.

Damnnnn, I've been looking at other dyno tests with that cam because I was thinking of replacing my XS290S with it, might need to order one! Those numbers would be impressive even if it was a 493.

Thanks !

And thanks to all that gave their input.

Mark

One thing I wanted to add that I thought was interesting, was the engine picked up a little power when we retarded the timing from 35* to 33*. We didn't go any further, and I am curious as to what would have been the result.

Mark

that's interesting because the 446 with victor heads that dwayne and bradh just dyno'd made more power as they increased ign advance.
wonder if it could be the cam events or if it could be the chamber mods that hughes did to the victor heads..

I read that too, and it's why I thought I would mention it. I thought that the more efficient the chamber, the less advance is needed ?

Mark

Can someone please explain why one engine likes less timing and another needs more ?

Thanks,
Mark

Years ago I found my 400/470 with E-heads liked 33* of timing on the chassis dyno. It would fall off 3-5HP 2* on either side of that.

davenc, I appreciate the info. I think we saw a little more than that. I don't have the exact figures. Nice example to compare with, that helps a lot.

Thanks,

Mark

Some times the timing light and the operator will see the timing different than you will see with your timing light, been there done that
Not every engine builder or hot rod mechanic will verify TDC exactly on the timing tab and balancer Never ASSUME anything, especially on race cars

I race with a guy that builds big engines and races a Top Dragster. He has a 669 that loves 25 degrees. He explained to me that the less timing a motor likes, the more efficient that motor is. My high compression 493 likes 34 degrees. I mean it HATES anything else.

I mean it HATES anything else. [/quote]
Not really, most BB Mopars, iron or aluminum heads, like 34 total the best that I have tuned and raced 35 or 36 degrees would run very close, if not exactly the same ET, so why run more than you need to get the best performance
I do remember one well known SS racer that had a 415 HP 426 M.W. 1963 Savoy that swore his motor liked 42 degrees total but he didn't build the motors. I found out later why he thought his motor like that amount of timing, a early timing cover used with a later model balancer You have to verify every little thing on race motors

Andy actually pulls timing out to calm down the launch for racing. Not much and not for long but still, starting at 25 degrees? We also learned the other side of that as well. The car wouldn't run pulling more than about 6 degrees out of it. That's pretty amazing if you ask me. I've heard of some other highly efficient N/A big engines that like no more than 28-30 as well. It's become my goal, big(ish) engine that likes 28 degrees!

Cab, I can say without a doubt that the tab on this engine is correct, with zero on the tab and balancer being tdc . It is something that I always check. The dyno shop that we used builds some high $ engines and do a lot of dyno work. I am confident we were @ 33* . We started @ 35* and then backed it down. I know my Hemi likes 32* .
Thanks,
Mark

This is what my understanding is as well. The more efficient the engine, the less timing advance is needed. Don't the Gen 3 Hemis run less timing ?

Thanks,
Mark

Nice build! That is about the same combo I have in my Challenger. 470, Eddy RPM heads, (I had Dwayne do a little porting on mine. I think around 293 cfm) RPM intake. Nyutten 750 carb. I'm running about the same cam specs in a mild hydraulic roller. I always thought this motor felt better then the 500 hp I was going for. Now I probably know why. I might try a Fitech in the spring.

I messaged Mark about this cam a while back and purchased one for my mild 440. That cam is the cat's ass..Has good power and pulls like a freight train.

Not surprised how well his 470 runs as you can see his meticulous detail on his Hemi Allstate..very good numbers!

Thanks Chris,
I appreciate the complement.
I am glad that cam worked well for you too !
I wish we would have flowed the heads after they were finished , but we didn't.
We did use a windage tray from 440 Source as well as their oil pan.
The distributor is from Fire Core.
Thanks,
Mark

Put a bigger carb on that thing and hang on............a 750 barely belongs on a hot small-block...........

Nice numbers on the 470!

I have nearly the identical engine. The only difference is my Edelbrock RPMs have not had bowl work, my carb is an 800 DP, and my cam is a Comp solid roller.

My Firecore distributor is set at 24 initial and 34 total. I think it needs more initial and maybe slightly less total advance, but the snow came early so I'm done until Spring

I apologize if I am hijacking Mark's thread but I am wondering if some of you experienced builders would like to speculate whether my cam:
( http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=741&sb=2 )

would, all else being equal, make more or less HP/TQ than Mark's cam:
( http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=731&sb=2 )

Any takers?

I thought I recognized that dyno room! Dale and crew are good people. My 434 small block was dynoed there.

Nice combo Mark.

What ratio rockers are you running now?

GSS ,
Thanks, and no problem on the comparison.

Mark

Thanks Justin,
Dale and Nick are great to work with. We had a good time, as always. We are looking forward to going back with my Hemi.

Mark

My 11 second stock stroke 360 ran faster w/every bigger carb change and ended up w/a speed demon 850 that flowed 920 cfm, you are choking that poor thing just look and ask around and even small blocks are picking up bunches going from 4150's to 1050 Dommy's..........Just trying to help.........

I had a ball when we did mine. It took most of the day so I had lunch with them. It was like sitting down with old friends I hadn't seen in a long time. If they were closer Dale would have to run me off or put me to work. lol

My 11 second stock stroke 360 ran faster w/every bigger carb change and ended up w/a speed demon 850 that flowed 920 cfm, you are choking that poor thing just look and ask around and even small blocks are picking up bunches going from 4150's to 1050 Dommy's..........Just trying to help......... [/quote]

Going back to 1984 when I was running my '71 340 Cuda in Street class, it ran a best of 12.39@108 with a .590 sft cam and 4200 verter and 4.30's and stock 2.02 heads, no porting, and an 850DP. I got fed up of racers telling me that the carb was miles too big, so I put the 750DP that came with the car when it was a milder set up back on and lost 2 tnths. In fact, I persuaded my mate who ran a Mk1 cortina with a Rover 3500cc V8 (buick 215ci motor), stick car to try my 850DP, he just laughed but tried it....he ran 2/10ths quicker, should've seen the smile on his face!!...lost some throttle response of course but went quicker and back to his 600 holley......

[/quote]

My 11 second stock stroke 360 ran faster w/every bigger carb change and ended up w/a speed demon 850 that flowed 920 cfm, you are choking that poor thing just look and ask around and even small blocks are picking up bunches going from 4150's to 1050 Dommy's..........Just trying to help......... [/quote]

I agree with that. I am surprised the difference in peak HP between the Quick Fuel 780 and the Demon 1050 was only about 10 HP, if I am reading Mark's dyno sheet correctly.

I was planning on a Holley 4150 1000cfm for my 470. Could probably handle more than that, but it is a street car.

Mark, what is your initial timing?

I agree with that. I am surprised the difference in peak HP between the Quick Fuel 780 and the Demon 1050 was only about 10 HP, if I am reading Mark's dyno sheet correctly.

I was planning on a Holley 4150 1000cfm for my 470. Could probably handle more than that, but it is a street car.

Mark, what is your initial timing? [/quote]

The peak power for the QF 780 was 571.17 torque was 604.19
The Best Demon pull was 584.98 HP and 621.32 trq.
We didn't check the initial timing, just the total. We started @ 35* and backed it down to 33* and picked up a little less than 6 HP. and 12 lbs ft. trq. with the 780 QF
All pulls with the Demon were @ 33*.
For some reason the first full pull on the engine made power to 6,000, and was climbing. It never increased in power there again. All done climbing @ 5750 RPM. Tired springs? I don't know... It has set with the valves adjusted since 2014, I just turned it over by hand occasionally.

Mark

Looking back at some of the data on the dyno pulls, I noticed that the first few pulls where the engine peaked at higher RPM that the water temp was higher, and the left and right banks were more balanced AF numbers.
Is there a relationship to the higher RPM peaks and balanced AF numbers ?
These were the first pulls tested above 5,000 . We made the very first pull to 5,000 as a test to be sure all looked good.

Thanks,
Mark

What can I expect out of the Edelbrock springs that came with these heads? Are they a good quality for this application, or should I consider changing them out to something else?

Thanks,
Mark

Do you know what pressures they had on the seats and opened? If so remove several and retest them to see
It wouldn't surprise me at all that they have lost 20 to 30 Lbs. every where
I like to use 140 to 160 Lbs. on the seats and from 325 to 375 opened on both hydraulic and solid flat tappet cams for street use with stock valves, add a tiny bit more pressure(10 to 20 lbs.) on both for larger, heavier valves

I have a customer with a 446 I built in 2005 running that cam with RPM heads, who has been enjoying his car on the street and strip since then....... Still has the original springs that came on the heads .

Cab, I checked my notes and I don't have the pressures listed. It was about 2007 when the heads were prepped. I was planning to use a hydraulic FT (XE284 I think) at that time so those were the specs provided to the machine shop to set up the springs.
Dwayne talked me into switching to the solid cam, for which I am grateful I should add.

Thanks,
Mark

Well that is encouraging Dwayne ! Does this engine's RPM / power range look like what you would expect from this cam? I am very pleased with the outcome, just curious about the RPM range, and why it started peaking @ 5750 when it had pulled to 6,000 and was climbing then.
Thanks,
Mark

I would pull a couple of springs to find out what pressures they have now
There is always a reason for a motor to change readings like your seeing, sometimes figuring out exactly what caused it is the hard part
Hopefully the cam is okay

Boy what a torque monster Congrats on your build

That's really impressive for a smallish cam and "a little bowl work" (!!) on a set of RPM heads to be able to get that much torque to carry that high in the powerband... it's a testament to a really well thought-out combo...congrats!

Thanks Cab,
I will investigate the drop in RPM for sure. I will have to invest in spring testing tools.
Mark

Thanks Dave,
It is even stronger than I hoped for.

Mark

Thanks Wise,
This site and the helpful contributions from guys like yourself, Andy's book, Dwayne's cam choice and some quality machine work, really make a difference.
I wonder how that stock RR converter will respond to the torque !?

Mark

The 440 I referenced peaked before 6k, so I don’t think I’d expect more cubes with the same heads/cam combo to peak any higher.

Id say if the 6000 peak only occurred on one or two runs, it could be an anomaly during testing, or some heat soak in the manifold cost the motor some upper rpm power.

It certainly won’t hurt anything to test a few springs if you feel like you “need to know”.

I might check a few, just to see where I am now. Having this information to compare RPM power pk. is what I was hoping for. I think I am good to go.
Thanks Dwayne ,
Mark

Nice build! I have to admit, much stronger than I would have expected it to be!

Chip, it is much stronger than I thought it would be too. Now I am wondering about the rest of the driveline. Especially the trans front drum, but also the tired old 489 cone type suregrip.......
Like that old saying, "Be careful what you wish for" !

Thanks !
Mark