Just my 2 cents,
These are over the counter universal, SB or BB smog base’s because they have the outlets for both.
Assy. Line have only the SB or BB rear tube with the one face it forward to the pump.
Also the studs that are in the pics appear to be 5/16” where Assy. Line I believe to be 1/4’’.
I have an NOS Small block smog filter pt.no. #6422287
Tube only out the back to the breather tube hose and a tube out the front to the pump hose
And it has the 5/16 stud
Joe

Since we are on the subject of drop base air cleaners, I have one in my stash that has no tube holes punched. Blank spots whrer they would be. Seems like this would be a pre-smog application? I was trading parts back in the 70's with some guys in the neighborhood and one of them had a 65 396 Corvette. Possibly from that?

No tubes was only used on the L88 to my knowledge.

Jason

That makes a bit of sense. Guy down the street had a 71 LT-1 Corvette and he bought an L88 hood from GM. I remember he used it with the original LT-1 air cleaner base so somehow I ended up with the L88 one. As it happens, he still has the car an lives across the street! I'll ask him. Thanks. Explains the black lid I have also.

EDIT: Doesn't explain the black lid. I remember now the L88's only had the flame arrestor with the mini lid. Hmmmm...

I just pulled the air cleaner from my 67 L79 California car (with K19) and it only has 2......one for the A.I.R. pump and one for the crankcase breather.


Tim