1994 GMC Pickup engine swap - advice please

[piecesparts]

Are you doing the motor in the truck or the one that you are going to put into the truck. If the motor is sitting on the shop floor, I would consider a "Leakdown test" over the compression test. It will tell you whether or not you have a weak cylinder and possibly where the problem is. The motor would not have to be cranked over to get this done. If you do this then look for a good percentage number on the cylinders below the number of 25%. A real good moter would be at 5% or less on the cylinders.

If you do a compression test, I would be concerned if any one cylinder was a lot less than the others and if the compression on any cylinder was below 110#. This shows some wear and tear. In the old days most cylinders on vehicles tested out at about 125# and that was considered really good. Life really doesn't change much in this area.