Pull the intake and use a feeler gauge to find out what thickness intake gaskets you need Also you need to know that the intake manifolds need to be torque down multiple times before starting the engine to insure they are going to stay tight, torque down. I use a inch lb wrench and torque the center four bolts and studs to 72 inch lbs, the remaining outer ones get torque to 48 inch lbs I retighten until none of the bolts or studs take any more movement or torque Retighten them again after warming the motor up also I use a aircraft gasket sealer on the fiber intake gaskets, not on the teflon coated intake gaskets These old motors, heads and intake can be cut a bunch of times before you get the parts Sealing the intakes on both the B and RB as well as the 426 street hemi and race hemi can be challenging