i was thinking about porting my intake manifold, because I wanted to paint it. What size, and what kind of gains could I expect.
Thanks

 

Not much without ported heads and a good sized cam.

 

Probably not much without porting the heads.

I had Lloyd Port mine after I got my heads back from him.
I looked at my heads, and then my STOCK LT4 intake
and thought to myself. "I need to port the damn intake now!"

The ports on my LT4 heads were cc'ing 217 after and flowing 289

 

I just changed my intake gasket on my lt1.... second time now (first time was my '94 lt1). Looking at it, looks to me like stock heads need porting way before stock intake does.