perplexing situation

[Chevy454]

The first L72 I put together came in at 10.2:1, after a slight clean up on the deck, with the stock TRW pistons, and the .038" Fel-Pro...unless it was the dead of summer, I ran it on pump gas...took our Y-Camaro to 12.7s @ 108+ (woulda been better had I known then what I know now!).

[jasonL78]

Tommy great topic! I am asumming this is the motor for your 68 BB nova? I was pondering the same thing with the new motor I am building for my 68 L78 nova. I have a stock l78 short block assembly with the 11:1's and my machine shop told me to change them as well. This topic just changed my mind to keep the high compression slugs. Do any of you use the high test from the pump (93) and then use an over the counter additive, like octane boost 104. Or should you just use race fuel like cam 2?

Jason

[Andy]

What are the cam specs that are going into these L78s? Have the blocks been decked? What CC are the heads, and how many CCs do the pistons displance(valve reliefs[flat top], domes[dome top pistons], dishes[dished pistons])? I bet that you could get an aftermarket grind from comp, crane, crower, lunati, or isky that would make more power, and would allow you to run pump gas. With the problems mentioned with some of the reformulated race fuels, it probably wouldn't be a bad idea to build a motor that would not have to have race gas. Most of our cars sit up at one time or another and who wants to deal with the hassle of rebuilding carbs or draining fuel tanks.

[Chevy454]

Fellas, I'm telling you, with the stock pistons, on a 34cc dome, you'd be *lucky* to see 28cc across the board (more likely gonna be 26-27cc each)...don't get wild on decking the block (a little is ok)...run the good Fel Pro .038" head gasket...and I bet you'll be right at 10:1, especially being we're talking 396s. Even better, go buy a cheap cc'ing kit (well under $100), and check it out for yourself...

I would recommend the Crane/GM blueprint '143' cam, as I believe it's a better cam and I'll just about bet it'll be cheaper...

We raced our stock spec L72 on pump gas all the time, except in the hottest part of the summer we'd add just a splash of race fuel...I'm not a fan of the octane booster stuff.

[Tommy]

Jason, the engine is for the 68. I talked with the builder today and we will be using the factory stuff. he was fixing to check the pistons out for wear and tear, the cylinders were good. I spoke with a guy at Crane today about the 143 cam and will be using it as well. Rob, thanks for the information you sent me .

Tommy

[ORIGLS6]

Tommy,
That Clary kid might still be wet behind the ears,...... but he knows his stuff on these old engines!

Gonna be interesting to follow the progress of a certain Red Chevelle now.