I took a set of hooker shorties off of another ls1 and am going to put them on my car.. However, i didnt think to keep any of the bolts? Will the stock bolts from the manifold work to bolt up the headers?

and also, ill need a new seal for both headers where they connect to the Ypipe? Any suggestions on where to get those???

 

you can re-use the stock bolts no problem. If it's anything like the stock system there are no gaskets on the y-pipe so it should just bolt right up.

 

I second using the stock bolts. I had my original exhaust manifolds pulled off, then my original bolts put back on, then when I pulled the heads, I pulled them off again, and put em back on, and they're still holding up well.

You can PROBABLY get away with reusing the gasket, but its so cheap, I say replace it.