I have a '52 panel with a 350. While installing a new radiator, I switched the thermostat housing to a TransDapt aluminum swivel housing with an O ring. This was back in the summer. It now leaks from what appears to be at the joint where the neck meets the base. I plan to put an aluminum one piece on (with a gasket) but I don't know what size and pitch the original bolts were (I thought I put them in a place where I would remember where they were. But that didn't work!). I want to get everything ready before I start so I don't have to take the old one off, go to the bolt store, then come back to complete the job. The bolts that came with the TransDapt housing are cap bolts that use a Allen key to tighten and I don't think they will work (they recess into the base). Also, I've found on-line that some people recommend putting studs in the manifold and attaching the housing with ny-lock nuts. Any thoughts on this? Thanks.

It's a small world, but I wouldn't want to paint it.