Been struggling with changing anything on this 89 Formula, everything is so original and everything works. Pulled off the air cleaner tonight, found a very old air filter and what I can only guess was part of the hood liner in the base and completely blocking the snorkel. Decided to keep the factory base and put the spectra top on. I will come up with a grill for the cowl that can block water but hopefully pull some cooler air in through the top. Regardless removing the rat from the snorkel alone should help this thing breathe better. I will drive it to work tomorrow and report how she drives.

 

Several sources suggest that those "filter-lids" actually reduce power; at least on carbureted applications.

The theory is that they disrupt smooth airflow, cause issues with air bleeds if not the main fuel discharge through the booster venturis themselves.

Whether any of that applies to fuel injection--TBI or otherwise--I don't know.

Any "cowl induction" that isn't SEALED to the air cleaner is a waste of time; and has the potential to reduce the cooling system's effectiveness. High-pressure "cowl" air bleeding into the engine compartment reduces the amount of air coming through the radiator. All the OEM applications of cowl- or "cold" air induction; or even the Trans-Am middle-of-the-hood cold-air induction were sealed to the air cleaner somehow--rubber gaskets, foam gaskets, hard-plastic ducting, etc.

 

This air filter obviously is a big improvement over stock. Heck, they used it on 350 Corvettes.

 

And now, all that OEM cold-air plumbing is wasted.

I can understand that the OEM cold-air plumbing may need to be enlarged, depending on engine displacement and RPM; and the heated-air intake could be overridden with a simple plugged vacuum hose.

Ignoring it completely, I don't understand. I'd have killed for that stuff when I was dicking with a '66 Biscayne in the 1970s.