No I have a slant 6 71 Demon that I put a 383 in, they are all basically the same..
I'm using 2" under chassis headers, so shimming was needed to make everything fit.. I have stock big block isolators I'd sell - 1 already cut for the big block oil pump if you wish to try them? As I ran into the same problem you're having - and bought new 2" thick big block rubbers, but they were to tall for my setup, made the trans hit the tunnel, so I bought the Schumacher shim kit and a fox Mustang torque strap (I have an aftermarket K member).. PM if you're interested in the mounts - I'll sell them cheap
