IAT's make a big diff as well. If the Intake Air is too hot then you can't run the DCR you think you can.

Bret

 

Listen to Bret. Be very carefull what you choose. I live in the middle east. My CR is pretty high but we thought we could get away with it with cooling, doesnt always work out that way. I was seeing insane IAT temps while cruising. On a cool night it ranged in the 100's. On a full blown hot summer day I would see 140's +-15 when cruising. Now I'm scrambling to find ways to stop the real knock. Even with all the timing pulled out I see knock in very hot weather. Do yourself a favor and choose wisely or pull your hair out everyday like me.

 

Well if ya had a triple row 1" radiator,the LARGE Mizner pump and Evans coolant(not anti freeze)ya should be able to run 8.5. I have done it with 9.0 with that set up and the temp here gets into the high 90's and low 100's.

On the shop car I have a J&S programmable timing retard,but most people won't spend the 600 dollars to get one.In other words if only one cyl is rattling ya don't have to pull timing from all cyl's just that one and ya can do it in small increments.

You also have to build it with anti detonation in mind. Ya can't just say ya got 8.7 with a .050 quench and things like that.

 

I've asked this before, but does anyone know the IVC on the stock LT1 cams?

 

I have a 388 that runs on 93 Octane, and I have 11.7:1 compression and the underhood temps are horrible, LT's don't help that, running the stock radiator and 180 thermostat, here in TX, my car runs at 200 degrees so i'm needing a major tune, 160 thermostat, 50/50 mixture before my car will even run right. My IAT temps must be horrible.....................well just gotta have the money to do that first, runs great but not too great performance wise.