Stock LS1 Block with stock 243 heads/stock rockers and LS9 Cam (211/230 @.050 valve lift and .558/.552 lift with 1.7 rockers and a 122.5 centerline)

What size pushrod will i need? (stock)?

I'm assuming stock will work.

I have my reasons for this build (FI) so please if someone could answer the question I would appreciate it.

will be for my 2004 GTO

 

If the base circle of the LS9 cam is the same as the stock cam, then yes - stock will work. I'd probably measure anyway though, the pushrod checker is cheap enough.