Heat exchanger to head: stud size

[1987 Porsche]

I have a 78 911. When replacing the oil return tubes I had to drop the heat exchanger on the drivers side. When removing the heat exchanger I ended up snapping one of the studs and one came out with the barrel nut. I ordered new studs and the recommended size on pelican was 8x51mm. When they came in they were way to long compared to the ones that came out of the car. My question is does anyone know the exact stud size for my vehicle or if anyone ran into this issue? It seems like the correct size could be 8x37mm. Thanks

[HaroldMHedge]

Looking at Porsche's online PET. The correct part number is 999-062-237-02 for these studs and show them as BM 8 X 35.

http://www.porsche.com/all/media/pdf/originalparts/usa/911_USA_78_83_KATALOG.PDF

PP's online catalog lists these studs as being 8M x 51mm. I would contact PP to figure out the problem.

[chris_seven]

Depends if you thin or thick flange heat exchangers.

[1987 Porsche]

Guys thanks for the help. It does look like they should be M8x35 and I do have thin flange heat exchangers. Hopefully others could learn from this thread and not order the wrong size studs.