do you have to space off the windage tray? what about clearance with the ls1 block. seems like i read somethng about it at one point but i can't remember. and i can't ever seem to find anything useful when i search.

ok i found where it does need to be shimmed but how much?

 

I used a couple washers. It ultimatly depends on what rods you use, but shim it untill it fits. Just put the oil pickup tube under the windage tray so it does not move any closer to the oil pan.