I'm sending my stock heads to Lloyd Elliot, he recommended getting them milled .030 and running Impala head gaskets. Does anyone know what compression this would result in? He said he "thinks" about 11.4, I just want to make sure exactly what it is. What is the highest compression LT1's can generally run (no power adder, just an average heads/cam setup) w/o detonation on 93 octane? It will have tuning....Also, does anyone know what length pushrods I will need? I really don't have access to a pushrod length checker, and I really don't want to buy one, but I will if I have to. BTW thanks Lloyd for all your help thus far, you have excellent customer service Thanks fellas!

 

Use the CR calculator here: http://www.rosspistons.com/CR%20Calculator.htm and play with the numbers yourself. You didn't post any details of your setup, so the questions can't be answered without data you didn't supply.

Specifically with respect to the CR, you need cam specs in order to say what is the CR you should aim for. If you have a stock cam and are going to run 93 octane I would avoid mods to raise the CR much if at all. Just IMHO.

As far as PR length goes, assuming the current pushrods are proper length, you could just subtract the amount the heads are milled, unless he is talking about angle milling. That would be more complicated and would depend more on exactly how the heads were milled. But I'd advise against milling them in the first place.

Rich Krause

 

The cam is a CC306, so I definitely want to bump my compression up a litlle to help my bottom end power. Thanks for the link and advice!