I was going to weld in a vband assembly in place of the leaking band clamp at my y-pipe, the y-pipe that was the first exhaust pieces I ever made. The welds are fine but the angles suck, I cut them all with a sawz-all and two of my buddies and a good number of beers were involved. So I decided to replace that section, but then got to thinking with all the LSX motors making crazy power with factory manifolds, maybe I should use my old set? Right now Im running tri-y headers, with a lot of surface area of course then that Im sure Im loosing a LOT of heat out of, 2.5" outlets. The factory manifolds are 2.25" outlets.

Here is a pic of the 1992 technology factory manifolds...




Which do you think I would be better of going with? Keeping in mind, this is for a mid mount S400SX3-75 BW turbo. Spools fine just the way it is, but it could be better Im sure. This is all attached to a 408ci small block stroker, HP goals have been met a very low 550RWHP with 8# of boost, directed through a TKO600. The y-pipe will be bolting to 46" of 3" stainless pipe, double wrapped before it gets to the turbo.

 

That looks fairly restrictive, the lsx exhaust manifolds flow about like a set of shorty headers. Much better than those, no doubt. I wouldn't use those on a 408

 

Yeah, I figured, but I've never seen them in person so I thought it would be worth asking, thanks.