I’m prepping to replace a leaky gasket on the manifold to down pipe connection. I have the gaskets but (stupidly) didn’t think about the hardware. Looks like the stock hardware consists of 3 studs, each with a pinch nut on both sides. Would there be much issue with replacing that with a bolt and a pinch nut? I can get the bolt and pinch nut locally, otherwise I’ll have to order the stud or cut down an M8 threaded rod to make the studs myself.

 

Reports here show that results vary widely, but I was able to reuse the original studs and nuts with no problems. Others haven't fared as well.

 

I replaced a couple of studs from the exhaust manifold to the downpipes recently.

Stud threads are 8M x 1.25

You can find the nuts at Lowes.

 

Here’s hoping I can do the same. Is the hole in the flange threaded or does the stud slide right in?

 

The holes in the flanges are clean and not threaded.
Get yourself some copper gasket spray and coat the gasket before installing. It will help the seal.