When I bought my 65 Barracuda it had a 318 with truck mounts and it sat way too high air cleaner rub'd the hood and the 904 trans also rubbed on the tunnel
The guy who suggested the truck mounts used them without insulator and he said the passenger side needed a 1/2" spacer. I thought about just shortening them and redrilling the holes to use them with insulators. We'll see.