Side pipe exhaust to manifold nuts and bolts

[gooch]

These nuts and bolts connecting the side pipes to manifold are badly rusted.
Can anyone tell me what size and material these bolts are. I would like to replace them.
Thanks

[AC Bill]

High heat paint like VHT, or even BBQ paint will cover up the rust quite well....as they can sometimes be difficult to remove..

Allan headed 3/8"-16 thread, and 1-1/2" long are supplied with the pipes originally.
They may have come with stover nuts, which can be murder to get off. You could replace the nuts with new stover nuts, as they will not vibrate loose. Many just use a lock washer, and two regular nuts per bolt, the 2nd nut, used as a jam nut.

Replace them one bolt at a time, otherwise you will need to replace the gaskets too. If you do remove the pipes, make sure that if they have wedge shims, you make a note of which way they were installed, and reinstall them the same way, or the pipes may sit wonky.

[CraigS]

I use plain grade 5 zinc coated nuts and bolts from Ace. Nothing from HD or Lowes. NO locking nuts of any kind. I use two standard nuts on each bolt so I can run them on by hand except for the last couple of turns. 3/8 is standard. If you need to adjust the end of the pipe up and/or down a bit, go to 5/16. Fine thread for either.