I have a 1976 351w that i was having ignition issues with so I went on Ebay a bought an HEI setup for the engine. I've never owned a FORD V8 before, so I did some research on the differences between 302 and 351w. So I did. I bought the HEI for a 351w and it dropped in fine. no pump shaft issue. My issue is the distributor fits loose in the intake hole. When I try to tighten up the lock down bracket it srews with the timing. I have not found anyone with this issue. The distributor has o-ring on it to seal against the intake bore. The don't even touch. What am I missing? What can I do to correct the issue? Thanks for your time.