I installed ZZ4 heads and cam on my 1991 roller L98 motor, so I threw on a Corvette TPI base and it bolts right up.

Problem is, it seems the factory F-Body rail sits too high on the base and does not allow the fuel injectors to seat properly and eventually a couple of them will start leaking (badly)..

How should I fix this problem?

I do not have a Corvette fuel rail (just got the bare base) and was told the inlets on the TPI Corvette rail were different anyways.

 

Are you using factory injectors?
You may have to file the 4 rail mounting bosses down a little to get a tighter injector fit ?

 

24# blue tops

 

bump

Should I grind the manifold? Bore out the fuel rail?

 

Some fuel injectors (notably Ford injectors) are a bit shorter then stock TPI injectors. If that's the problem you're having, there are enough people that have worked around that problem that a search should give you the answer you need. I'm willing to bet it has nothing to do with the Corvette base.