Does anyone know off the top of their head what the size and thread count are for the header bolts on a 1967 289?

 

3/8-16 and all should be grade 5 or better.
Jim

 

thanks

 

Keep in mind that the bolt heads for headers have smaller heads than standard bolts out of the bin. You can usually find bolts designed for headers at your local auto parts store in the "speed section". Unfortunately, you may have to purchase two packs as the kits are often designed for Chevy small blocks which I believe only use six bolts per side.

Good luck!
Jeff