[Dragncar]

I wont even run a head that does not either have the ex crossover filled or welded. So what if it takes longer to warm up. They are old cars anyway, part of the deal. I swear I can tell if a iron headed Pontiac has stock crossovers vs filled.
Stock the ex note is kind of muddy. Cleaner- crisper filled.
Tells you all you need to know about the modification.
Paul would know this, I am not positive. I always thought Pontiacs, Olds and Buicks have 2 holes behind the center ex valves for warming the carb. But Chevy,s have one hole, not 2 side by side. And that is why the reversion is so bad with BOP engines. True ?