I just picked up a set of used crawford HFC. I know the connecting side to the Y pipe of the HFC requires new bolts and nuts to connect them up. Will I need new bolts and nuts to connect the HFC up with the headers? or is there existing I can reuse?

 

They use studs to connect the top of the cat to the header. You can probably reuse these, they'll get stuck on one end or the other, I don't really remember. But I would just get new hardware completely.

 

Oh ok... so they have studs coming out from the headers to align the cats just like how the OEM cats has studs coming out to align the Y-pipe?

 

^^ Sort of.

The exhaust manifolds each have one stud facing toward the ground, and each cat has two studs facing up towards the engine. Also, the stock cats each have two studs in them to attach to the Y-pipe. You will need a total of eight new bolts & lock washers and 16 flat washers to install your hfcs.

I could be backwards on the cat-manifold connection, but if you get enough to do two studs/side, then you won't come up short if it's one stud in each cat and two in the manifold.

I used grade 8 fasteners, purchased at Lowes.