my heads have casting number# 10207643 and in lt1 lt4 rebuild manual it dosnt list these heads as a casting number being installing on lt1 or lt4 motors.
anyone have any idea how i could find out the specs on these heads they came off of a 1996 lt1 motor from a z28.

 

i have a set of these heads on my 96z,they were installed from chevy before i got the car cause the original set were cracked..

 

Same stock castings on my 1995 Z.

 

You obviously did a search, to find out this casting # actually exists, so you probably already read this: http://web.camaross.com/forums/showt...light=10207643 I'm confident there are others as well. I'm surprised the search feature here, hasn't broken down, or wore out from the extensive amount of use it gets. Very durable!