The heads I am using on my 86 Iroc are supposed to match up with the exhaust ports on LS1 headers better than 3rd gen ones. Does anyone know if they will fit?

 

I dont think so.

 

If your talking LS1 no they won't , the LS1 exhaust port location is like a big block or small f***. It's the "D" shape. You'll need to search for headers w/ "D" shaped head pipe. If no such thing, I guess you could match the head to a set of retangle port headers..I wouldn't go to far up into the port though (less than1/4") shouldn't need much. Or find some old headers w/ the "D", weld cut and weld.
Just trying to help.

 

Thanks for the help guys. I think I will just try to port my existing headers as close as I can get to matching the heads.