C3 1968 Air Cleaner Base

[Jay L. Flinders]

I'm finally rebuilding my big block 427/390. I have had it for about 10 years now. One of the problems I have come across is that when I try to connect the air cleaner base tube to my valve covers it won't work. The air cleaner base sets down on the carb. to low. I have chrome valve cover drippers. I have heard that there are two air cleaner bases one for a small block and one for a big block but the only difference is the the tube configuration. If that is so do I have the wrong valve covers? Or what do I do? Any help is appreciated.

Thanks Jay

[Joe L.]

Re: C3 1968 Air Cleaner Base

Jay-----

You have been told correctly regarding the air cleaner bases. If you are using the correct connecting hose and 90 degree elbow connector, it should work. Now, all this assumes that you do, in fact, have a correct air cleaner base. If you have a small block base, the angle of the tube on the base might not be correct.

With respect to the location of the vent tube orifices, all big block valve covers are the same. So, while you might have incorrect valve covers for other reasons, the location of the vent tube orifices should be correct.

[Mark #28455]

not all BB bases are the same

The 1965 through 1967 BB Corvettes used a high rise type intake manifold and the corresponding air cleaner base had the 1" tube go straight out toward the passenger side valve cover and connect to the elbow in the valve cover with a 1 1/2" long straight rubber hose.

The 1968 and later Corvettes (except the L88) used a low riser type intake and the corresponding air cleaner base had the 1" tube pointing backward at about a 45 degree angle (toward the number 8 cylinder) not directly to the side of the car. The rubber hose used with this style air cleaner was shaped more like a "U" to connect to the metal "L" in the valve cover. This style air cleaner also doesn't work well with aftermarket Holley double pumper carbs as the tube hits the lever for the accelerator pump.

Good luck,
Mark