[84 400]

You want the fuel pump for the frame truck your going into. Also be aware in 1986 SBC used a 1 piece rear main seal and different flex plate. Always something to look out for when swapping engines. Guessing one truck is a th350 and the other is a 700r4? i know your going into an 85 and not an 86 but who knows what has been changed.

This is a great time to replace the rear main seal and oil pan gasket. I like the one peice felpro oil pan gaskets. Its a great time to knock in new freeze plugs and give it a nice coat of paint. Do you need too? Maybe not but after having to do a rear main seal in a rig a week after a swap i will always do them on the stand before.