The rebuilt B20 (high compression engine with an Isky street performance cam and SU carburation) has only been on the road for a very short while, so I guess one should expect some of the problems I’m dealing with.
Anyway I think the timing and carbs are sorted out, and now I noticed a leak from the intake/exhaust manifold. I guess you'd call a good size vacuum leak. The car acts like it too – backfiring and popping as I try to start it.
A mechanic friend of mine says the thing to do is to back off the manifold nuts and then retighten from the middle out toward the back and front of the block.
My thinking is to put in a whole new gasket. The car sat under cover for the winter after the rebuild last year, so I’m really just breaking it in now.
Can I retighten, or should I get a new gasket? If I go new, what kind should I get? The one in there came with the IPD rebuild kit?

My appreciation is offered in advance.