Hi olddan and welcome. Yes you will have to cut it out. Get some motor mount towers from a 63 and up truck drill the front a arm cross member you can still reach in there to bolt them in like the 63 and up, it's just not as easy. space the frame rails up to meet the towers at the top about 1 1/4 inch. then use the factory mount cushions for the 63 and up. Dont use the U shaped bracket. it will allow way too much rock of the engine. It's a pain to put on or remove with large balancers anyway. BTW, you will need to have the transmission in place BEFORE dropping the engine in or you will not have any fun at all getting the tranny in there between the extreme lack of floor clearance and the torsion bar x-member.
Also, you will most likely loose the original e-brake setup due to driveshaft interferance.
I hope this helps and isn't something you just learned the hard way...
Last edited by Longbed61; 06/17/2011 10:58 PM.