I bought adapter plates off ebay. They need to be the 1" offset toward the rear. I know because I bought standard ones and the engine/trans were 1 inch away from making on the trans crossmember. They weren't anything fancy and they got the job done.

Exhaust manifolds and 6.0 dual exhaust did fit with the 1 inch forward offset. The exhaust may need massaging with a ball peen to clear the trans cross member when the engine/trans combo is in it's proper position.

Wiring was done by me with alot of help from Brendan's site: LT1swap.com. He also flashed the computer for me removing the vats, tire size change, gear ratio change and transmission program(4L80E to 4L60E).