Header gasket issues

Been blowing gaskets BAD since I put the eingine in the IROC. I'm using the same headers, same turbo, same size downpipe, everything is the same minus the placement of the piping to the turbo. I'm on gasket #6 so far. I ordered a set of Mr. Gasket aluminum gaskets the other day and some 5/16 headed bolts (where were these years ago?!) so I could get em nice and tight. Well I stripped out a header bolt in my LE Trickflows. So now I'm pissed. Gotta helicoil it but I want this problem FIXED.

Been running Felpro 1406s. They last about 3 weeks usually. The headers are 3/8" thick IIRC. Only difference in the new car is that I have that cutout. When shut it feeds to a 2 1/2" exhaust that necks to 2 1/4" out the back.

Might be putting too much back pressure on those gaskets while forcing the exhaust through that smaller piping.

Kinda what I thought. Considering converting them to the Stahl pattern flanges, they look like they'd seal better. I'll have to read up on it.

Get bigger exhaust. Problem solved.