L-72 Dyno Test

[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).]

[Mr70]

Very Rob.
I and Steven J and also waiting to see how you perform at the PSMCDR soon.
Glad the heads worked out.
Hello 12's

[Chevy454]

Sorry to dig this up, but I thought I would post some of my results, in case someone ran across this thread and wondered how I did.

At the Pure Stock Drags in Michigan, I was battling a bad set of poly-locks on my rockers, but did manage a couple of 13.0's. A few weeks later, I went to Gateway for a test'n'tune, and ran 12.95@108 on a crappy 2.4x 60' time the first run out of the trailer. Haven't been to a track since.

I'm still running the set of straws (chambered exhaust) on the car, but I am hoping to get a good mandrel 2.5" system and let the 427 breath for a change. We added a rebuilt rear end (went to 4.56s) and also a rebuilt tranny/converter a couple of weeks ago, and it feels a LOT stronger. Hoping to try my luck at Norwalk on the 13th...we'll see what happens!

[COPO PETE]

I'm thinkin' 12.70's at Norwalk for you Rob. That track is great!!!!!!! If not, I guess I'll have to make a pass for you.....not to put any pressure on ya!
Peter [img]/ubbthreads/images/icons/shocked.gif[/img]

[Chevy454]

I hate to make excuses, but I'm still running that crappy chambered set-up. I tell ya, I was within an inch of ordering up a Flowmaster system yesterday, but I restrained myself. I talked to Pennington and he said the chambered system on his '68 cost him 3 tenths versus the Flowmaster system...it just sucks knowing a TON of my ET is sitting in that friggin' exhaust [img]/ubbthreads/images/icons/frown.gif[/img] .

[Chevy454]

I finally got the "straws" off the Camaro yesterday. Check out the stock chambered tail pipes (which we have been running) compared to a set of 2.5" Flowmaster tail pipes (which everyone else has been running):






A lot of the places in the chambered pieces weren't even 1.5" in diameter! The Flowmaster pipes look like sewer pipe compared to the stock stuff!

[Stefano]

Rob,
We had a local speed shop dyno test a stock exhaust but for headers on a warmed over 454 LS5 Chevelle vs a 3" inch mandrel system and it meant just over 50 rear wheel HP and 4O foot pounds of torque. Those stock systems with all the crimps and bends are very restrictive.

I installed a set of 3" mandrel bent Torque-Tec pipes with individual 13" Flow Masters on my Ohio COPO Camaro.

The exhaust fits great and sounds even better. It is a bit obnoxious and does set off car alarms on a regular basis.

The car runs a stock L72 +.030 but for L88 spec cam, MSD, Hooker 2" Super Comps. I am taking out the original BE 4.10 rear and swapping in a 4.56 set up.

I have a set of 9" M/T E/T Drag Radials mounted and ready
to go.

I will try to test the set up within the next Couple of weeks.

I just hope the Muncie trans holds up.