I know there are a ****-ton of threads on here about LS headers for a third gen . My question is does anyone know exactly where they hit and need modified ? My brother and I are building a bracket car out of a '91 RS , it's been back-halved and has 2×3 frame rails going to the factory front clip. Now , the part of the factory clip that bends around the bellhousing of the trans is gone , so if that was one of the areas its not a problem . Second , we are gonna use a front plate instead of frame mounts , so the engine can be moved front or back and up and down if need be to gain clearence around lower a-arm mounts , crossmember , etc. So if anyone knows if being able to move the engine and the frame clearance will make 4th gen headers usable , the info would be appreciated .

 

Different mfrs put the primaries in different locations so one fitting may not allow another to fit

Biggest clearance issue is the front frame rails on either side of the bellhousing. 4th gen collectors kick out to the sides directly into the frame. If your racecar has this cut out, give them a try

 

That's kinda what I was figuring , thanks for the input .