So a while back I picked up the ARP 144-1202 header bolt kit in prep for my TTI W2 build, and while these are nice, they are just too short to work with the hefty flanges on the TTIs. These bolts are all 0.750" UHL.

Looking through ARP's catalog I find 641-1000, which is a 5/16-18 bolt but with 1.000" UHL...seems like that's exactly what I need.

Strangely though, ARP does not list an exhaust header bolt kit that is a 5/16" with 1.000" UHL.

So I'm wondering: are these the same bolts as the ones in the kit, just longer?

Heck, these are only holding the headers on, so I can't imagine the materials would need to be all that different...but what do I know about materials sience...LOL, so I thought I'd check-in here.

Thanks!