I know you are suppose to have an LT4 intake for LT4 heads but does it also go the same for an LT4 intake hooked to some LT1 heads?

 

I doubt the ports will seal correctly. Besides, the LT1 intake flows more than enough air, and it's the correct intake for LT1 heads.

 

I beleave you would have to have the LT4 intake machined for bolt holes to fit the LT1 heads. I THINK that's what I read one time. Maybe someone can verify. If that's wrong, just ignore me

 

I just went through this with a local machine shop and he used one of my gaskets and lined up the bolt holes on my LT4 intake and lined up the bolt holes on an Lt1 intake he had in the shop and eveything lined up the same. I had always heard that the LT4 intake ports were .010"(something like that) inches higher than the LT1. But the only difference I saw was the amount of material above the ports on the intake was more than the LT1. But again other than that everything else lined up

 

There's an interference between the edge of the LT4 intake and the valve cover rail on the LT1 head. It has to be machined.... either the head or the intake... to allow them to bolt together properly. It won't do you any good though... the LT1 and LT4 intakes are virtually identical, except for the provision of extra metal at the top of the LT4 intake to allow it to be ported to match the 0.100" raised runners on the LT4 heads.

Bolt pattern is the same.... port dimensions are the same... only the valve cover rail interference is a problem. But then you won't gain anything, since they are "the same".