1. I can't answer directly, but I remember a raging debate on this question on another site, I am thinking either Performance Years or Team Camaro. There was an engineer who pointed out that Grade 8 is more brittle than Grade 5 and cautioned about a universal use of Grade 8 for replacements - especially at suspension points. My recommendation is to purchase direct replacements for bolts from reputable Pontiac speciality reproduction part houses like Ames, Classic Industries, Performance Years. Another good source would be clean, rust-free used bolts from us here.
4. Those "washers" are designed to either be welded on top of the mounting point surface or welded in flush to replace the original hole. There is debate on which method is correct, but one thing for sure - they need to be welded on.
5. All pontiac V8's were identical on the exterior so they use only one motor mount. So, yes, the 400 motor mounts would work.
I check your site at least once a week and see you have reach a bit of a lull after the rear quarter panels.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
