I read thats it 10.4 - 1... but a dude at a machine shop told me our cars really run at 9 1/2 - 1 because the PCM retards everything.

Because I want to run my car at 11 - 1 because I want to spray... but he is saying that I can't run my car at anything more 9 1/2 - 1 because anything more then that can't use 94 octane. Is this true?

 

Stk LT1 F-body CR is 10.5:1

Your dude at the machine shop needs to stop smoking the good stuff and brush up on his Gen 2 SBC specs.

Tony

 

Addtionally, its not static compression ratio that determines the octane requirements... it "dynamic compression ratio" (DCR). DCR reflects your cam specs.

 

The PCM retards everything? huh? Compression is set in stone....yeah - it is 10.4:1

11:1 with a cam around 270/280 and some chamber smoothing will not detonate.

 

Well i'm gonna have a LE2 setup for a 383 stroker... want a 11 to 1 cr but the dude told me that I can't run pump gas with that setup... sounds a little funny to me. Says that the timing is retarded to stop pre-detonation...

So this dude is just full of it?

 

He don't know what he is talking about.
Our shop car is 12.98 on pump gas with a 9.2DCR.If ya give me your engine details and cam ADV numbers I will figure it up for ya.

That 270/280 figure has got to be ADV duration

 

So is this guy the one doing your machine work? It may not affect his machining ability, but I would still take my engine somewhere else. Sounds like this guy doesn't have a clue.