if you want to utilize a whole CRX unibody, you'll need to push the firewall back 5-6 inches for a 350/400SBC. fab up some mounts, chopping the tranny tunnel isnt hard at all, and just fab up an IRS in the rear, or back half the car and go with a laddar bar suspension setup, only problem with that could be the potential length, or lack thereof, of the driveshaft.. It's not as hard as people want you to think it is, it is just time consuming and for most people seems like a huge project when it really isnt.