the car that i bought has a red intake manifold. i a pretty sure that its a LT1 that someone painted but the list of mods that i got when i bought the car has not been the most accurate so i was wondering if there is anyway to tell the difference by looking at it? i researched this online and i found that if you take it off you can see some changes but i didnt know if there was a way to tell just by looking at it or not.

 

the Lt4 has taller intake ports 100 thousandths taller.unless you mod the intake ports of the heads the manifold would be useless on an Lt1.

 

well he said that he had jasper class II performance heads. whatever that means

 

There is a lot of bad info out there about the LT4 stuff. The first reply is better than most. I would like t clarify it further though. The LT4 HEADS have taller ports, the manifold does not, it does have more material above the ports to seal to the LT4 heads. Internally the LT4 manifold was nowhere near port matched to the LT4 heads it is actually the same as the LT1 intakes. The additional material above the ports on the manifold interferes with the valve cover rail on LT1 heads, if that material is machined off the LT4 manifold to make it fit LT1 heads it is ruined as an LT4 manifold.

GIZMO from LS1Tech was kind enough to post this picture to help everyone better understand the difference.
http://i85.photobucket.com/albums/k5...1/DCP_1456.jpg