Hi
I´m installing a Corvette base manifold on my TPI and notice that it has a coolant crossover at the rear of the manifold, close to the distributor.

Do you think it is OK to leave this passage open or shall I plug it as it is on the stock manifold? Will I get into any cooling troubles if I leave it as is?

Thanks

Leave it as is. The aftermarket manifolds have it and it promotes better cooling at the rear of the cylinder heads.