[Rick 427 Cobra]

427 engine mounts can be installed a number of different ways with the available holes and bosses on the block. Left to right and upside down. Only one way is correct. Its easy to make an error, I know, I did. Incorrect installation can cause what you describe. Before you start bending and slotting things, check and recheck this simple thing. I'm a small block guy now and I don't remember the proper key, but I am sure with all the FE powered cars some can take a quick look.