L-72 Dyno Test

[COPO PETE]

CHEVY454; In my cars I run all the timing in at 2500 rpm. 20 initial and 36 total.Good luck. Let me know what your dyno says!

Marlin; Cars looks like it's coming right along. I love the shot with the old 1/4's hanging in the background. Good luck to you as well.
Peter

[69yenkoman]

Marlin:

Your car is coming along good. I like the old 1/4's haning in the background as well. Looks like you are doing a super job.:burnout
:

[YENKO DEUCE REGISTRY]

Thanks for the kudos, I can't wait to drive it. I also saved the deck lid and tailight panel, and plan on hanging them together in my garage at home. Brian Henderson has an original '69 Yenko Camaro 1/4 hanging in his shop as well, they look cool!
M

[Chevy454]

Well, guys, it's final: we put the L-72 on the dyno yesterday, and it spun it up to the tune of 420hp@5,600. This was through the exhaust manifolds, of course, but we were more after a good "break in" for the engine, and to try so different settings (jetting, timing, lash, etc.). Needless to say, we learned a LOT! The settings we ended with (lash=24,24 jets=78,84 timing=40 degrees) are a little bit different than what Pete used, but they worked the best for us, so we stuck with 'em. Now, I had better go see about getting that thing between the frame rails...

[JoeC]

WOW 420 HP with exhaust manifolds. Sounds great. Did it have mufflers hooked up also?

[Chevy454]

No, no mufflers, but the "dyno guy" said that a good set of mufflers (like a DynoMax) wouldn't change that much, except raise the torque a shade.

What we did was tune for a broad power curve, versus a higher peak. When we found that, we stuck with it. From 5,100-6,000 it was making 400hp or more, and was in the 416hp-420hp range all the way from 5500-6000. 6000rpm was about the most the engine seemed to like to run...now the only problem is keeping dad from spinning it over 7k!

[COPO PETE]

Congrats Rob....12.6 here you come!!!!!!!!
Peter

[Rowdy Rat]

Rob,

Well done!

I'll be looking forward to see how you do at the PSMCDR this year.

By the way, did you decide to use the 291s with the big exhaust valves or did you go with the 840s?

Regards,

Stan Falenski

[Casey Marks]

GOOD DEAL !!!

Sounds like it's gonna be one bad hombre' !!!

Look forward to seeing you and the car in a week !

[Chevy454]

Pete:

I would be VERY happy with 12s, and I honestly feel anything better than low 13s (from my car) is GRAVY.

Stan:

Well, I unfortunately(!) went with the 291s. I talked it over with several people (even Pete and JJ!), and they all gave me the thumbs up, as they are legal. I say "unfortunately", because the set of 840s that I ended up with need ZERO work, and would have even been cheaper to build than the 291s I used. But, I had to keep the 840s so they could be documented...kind of a shame! Colvin is supposed to be checking for some paperwork, but as of yet, all I have is the info from his book and info from talking with him and others on the phone. So far, the scenario I went into detail about in another thread seems viable, and isn't as far fetched as I had originally thought.

This engine turned out really well, and is about as close to factory as I could have made it. It would have been done about 2 months ago if I had not been worried about factory specs! For instance, the stacked height+gasket thickness is equal to that of what the factory would have been. The only difference is the .030 overbore, which could not be avoided due to a couple of bad cylinders. I had to shave the heads .010 (another extra thing due to NOT being able to use my 840s!), but when I cc'ed them, they came out big (as expected). Like around 111cc average, where they are supposed to 108cc. Well within what you could have gotten straight from the factory. When I plug all of the #s into the compression calculator, I come up with 10.9+, so it is almost dead on the AMA spec. Our next engine may take these specs to their extreme and see what happens !

[Edited by Chevy454 (09-06-2001 at 11:54 AM).]