Red top from s13, non VVT
Silver top is non existing as far as i know
S14 and S15 both had black tops. There is a blacktop with a notch and a black top without. The notch is VVT.
The s15 blacktop has smaller holes for the coil packs.
The blacktops have T28 turbo's
The s15 has ball bearing turbo's
But all black tops are available as non turbo as wel.
You need a RWD sr20, no FWD or AWD, they wont fit because no RWD gearbox will fit those engine blocks.
any more info @5t341tH?