I have a comp cam 575 lift big block chevy timing specs are 32 to 36 can anyone tell me is that btc or atc? :eek:

That would be before top dead center (btdc); that also is a total advance number, usually in by 2500-3000 rpm, not an idle advance number. I usually shoot for 16-18 degrees at idle as long as the engine turns over well with that much. Vacuum advance is a whole 'nother issue if you have it.

Jody