Have a 53 GMC 1/2 ton Long Bed with a mustang 11 ifs installed and a new power booster mounted on frame.I removed the rear crossmember. It looks like I have to remove the front crossmeber where the back of the original 6 cyl. was mounted,to make everything fit. Am I correct? I an installing a 305/350 with a 12 in tail shaft and installing a new crossmember for trans. Any suggestions