Can anyone tell me what the stock specifications on pre '86 350 heads are. I am not really sure what they came out of or if that even matters. I need to know valve sizes, cc's, valve lift, ect.

 

Basically an impossible question to answer, given the information you have.

Get the casting number off the heads. You can go to www.mortec.com and there it'll tell you where to look and quite likely what they are after you get the number. Otherwise it would just be a guessing game.

 

Valve lift isn't a head specification, it's calculated using camshaft lobe height and rocker arm ratio.