1970 340 air cleaner dimensions?

I'd say 1/4" maybe. I can't remember if I measured it or not. I do remember that I used masking tape, to tape into the oval opening all the way around. I cut it even with the inside edge all the way around the inside. I then peeled it off and stuck it on the side of one of the orange air cleaners to see what the I.D. of the holes at the end of the ovals would be. It didn't work out like I thought it would, so back to the drawing board. :BangHead: