I was lucky enough to have a customer bring me a 472 Hemi crate engine last September to confirm its health (dyno) and then make it the way he wanted it. When rebuilding or reconfiguring an engine I LOVE it when I have a running specimen to dyno test as the BEFORE baseline. Longstory short the crate Hemi lived up to its ratings and made exactly 535 hp and some 550 torque in its as delivered state.

The customer initially wanted 600HP or better and I was all game but when we got down to brass tacks I didn't think that was realistic. This Hemi is slated for a 'Cuda with a Shaker hood with power brakes, and air conditioning and ultra reliable. It is to be driven to all events/shows etc... So that ruled out the single plane manifold, big solid roller cam and higher compression. I also couldn't go nuts with the budget. The customer and I settled on 550hp + as a goal once he saw how small the cam was. 242 @ .050 .530" before last 238 @ .050 .504" before lash on a 112 LSa.

We settled on checking the shortblock out, some headwork, cam change and manifold/carb change. I didn't like how the crate hydraulic flat tappet cam gave up well before 6000rpm and solid rollers just aren't reliable if you aren't on top of them all the time--so I went with a custom Comp solid flat-tappet with the nitriding and Howards EDM solid lifters. Head work consisted of bowl blending, guide profiling, and crisper valvejob. The crappy M1 dual plane was replaced with an Indy Arlen Vanke dual plane in order to work with the Shaker. Hemi's just don't look right with one carb unless its a 4500 so on went a 950 Ultra XP 4500 series.

Breakin was something of a stressful nightmarish event as I had a flat tappet failure earlier this summer and pulling the valvecovers 6 times on a Hemi is no fun. I'm also super paranoid about rear main leaks on big Mopars .

After breakin it was time to make an exploratory pull. Was I ever happy with how this engine turned out. No smoke, no leaks, no bad noises, lash didn't move more than a thou, and more power, and better looking. We ended the test session with 580 hp and 580 tq with a much nicer rpm'ing Hemi--Isn't that what they are known for? I am starting to see why so many people like the 2G Hemi. J.Rob

Nice. What compression ratio?

I went with a solid roller on my 572, 242@.050 and .628 lift, hemi's need lift so they can breath. I also went with a 112 LSA so if I ever can afford fuel injection, I am good to go with the cam already. Those are respectable numbers! Tim

Nice !

Just under 10-1 comp. Thanks, J.Rob

How big is the new cam?

Any before/after flow numbers?

New cam 242/238 @.050 .531"/.503" 112lsa

Flow numbers picked up about 15 cfm to 340 ish. J.Rob

I guess I didn't realize the cam data in the original post was for the new cam.

Playing devils advocate here...... Knowing that you're rather familiar with a wedge in the 470-ish size range.....

Do you feel there would be any real power difference if it were a similarly built wedge(nice heads, good intake and carb, smallish solid cam)?

The graph ends at 570hp@6000, and it looks like its still climbing pretty good.....How high did you take it?

Where did the factory cam/valvetrain give up?

^ i was curious about the same thing...if someone built a nice 470/400 with some cleaned up sidewinders or trick flow heads (~10.8-11.2:1 compression), good intake and carb and a cam around 240@.050 and about .550 lift...would they see similar numbers?

Here's one that is close:

http://www.hotrod.com/articles/440-chrysler-dyno-test-trick-flow-heads-intake/

I'm glad that krautrock and fast brought this up. See, I have a dilemma. I have always thought the typical Hemi guy was nuts...spending all that $$ to (usually) go no faster than a wedge. I got it though; it was the "cool" factor and I still get it because now it's my problem, too.

Not having a big garage budget these days, do I scrape and save and the build the Hemi I have acquired, or do I sell the hemi stuff to fund a nice wedge??

I know the practical answer, but those Hemi valve covers on the wall are talking to me every time I see them...lol.

If you can find a block that is affordable, then Hell yeah!

If you mean me...no I have a block, heads, etc. My quandary is to spend the money to build it, or sell it and fund a wedge build.

I am a die hard Hemi fan so I would say yes, but I also spent 3 years scrounging parts before I built my engine...I wish I would have went with an aluminum block instead of the world Iron one, but as long as I don't toss a rod when I am hammering on her, life will be good. Oh and if you do it, its the same money to build a 572 as it is a 426 if you are building from scratch so why not go with the extra cubes. Tim