looking for experience from anyone who has either gone too big and made pistion to valve contact or someone that knows what kind of duration and lift a stock pistioned shortblock can accept. this is on a car w/ heads that have been milled .030 and im looking at a 230+ on the exhaust side. i know that 230/591 clears on the intake side but im wanting to split the diffrence for as much exhaust duration as i can get. what do you guys think?

 

Be careful when looking at lift and duration numbers and evaluating them for clearances. You can have two camshafts with the same lift/duration numbers but have different charcateristics due to ramp speeds. Typically cams with higher ramp speeds will tend to get the valves very close to the pistons. The only true way to be sure is to actually check it. When you get around .580 lift you need to start watching out.

 

true, i just dont want to have a custom one off cam ground and not have it clear.

i suppose you mean like an XE-R lobe VS a standard or EX. thanks, i hadnt thought about that. the one in question was the fastech F1 and this one's going to be considerably larger. more like 234-8 5/80's ish on the exhaust side.