Zekein36, my '36 pickup is restored now, but before I restored it I ran it for about 50,000 miles as a sbc Chevy powered rat rod while I was in college. You can easily make your own engine mounts that will mount the engine without any interference with the existing cross members, steering box or firewall.
Back in the 60's when I did it at the front I used 2 inch square tubing woth plates welded to the ends to bolt to the frame and to the stock Chevy engine mounts. At the rear I used an OEM Chevy bellhousing with outward slanted engine mounting pads on its bottom and fabricated brackets to bolt to the stock cross member.
For an exhaust system I made my own headers copying a Doug's Headers tri-Y set and large reverse flow mufflers and an H-pipe. It was torquey and very quiet.
The home made engine mounts were bolted in and when I decided to restore it I just welded up the holes and ground the welds smooth.
