I just installed my J's Racing exhaust manifold. Other than the slight interference fit with the engine mount, it seems to have installed properly.

It doesn't move at all, I can't get it to bang or knock, but I really don't know if it could produce false knock. Should I leave it as is or should I clearance the manifold with a ball peen hammer?

 

I would clearance the mount ...... Just shave off a touch with a die grinder

 

I'd do what s2kt3 said or just upgrade to some inovative mounts they should clear no problem.. I wouldnt take a hammer to your new expensive header.

 

I had a similar problem with my berk header (J's replica) when I put it in. It rubbed the firewall a bit. Put in innovative mounts and have had zero issues since.

 

Do you have any exhaust leaks?

Would you have trouble removing the top rear bolt on the motor side of your engine mounts on the passenger's side? I think the innovative mounts would give you the clearance you need, but I'm not sure you can get it in past the header and you can't get the header in past the innovative mounts. You may be able to loosen the header to get enough wiggle room to install the innovative mount. FWIW I had the same problem as slowd16 when I installed my berk header with blown factory mounts and just installed the innovative mounts--but that's a totally different problem from what you're seeing.

 

just remove the aluminum mount and grind it a little bit, from the pics its contacting on the part of the mount that attaches to the engine which means it moves with the header the header doesnt move and smack it..... just grind it a bit and give a 1/4" clearance. done and done ....

innovative mounts wil cause vibration.... stock will work great with minor grinding done...

lee