Drop Base Air Cleaner Assembly

[mr0077]

Many of you may already know this, but for those who don't, and are having a clearance problem between the hood and the air cleaner on their Cobra...

The 14" air cleaner on the '68-'70 big block Corvettes (and LT-1's I think) has the lowest generally available base for use on a single Holley carb. It is about 2 1/4" from the bottom of the base to the carb gasket surface, and is low enough that with a 3" filter element, the K&N Extreme lid will hit the air horn. This means that you can run an Extreme lid with a 3 1/2" element, a 3" with a dome-top metal lid (a flat or low-rise lid will also hit the air horn), or you can mill off the air horn to use a flat or low-rise lid or the Extreme top. Consider that milling the air horn with this base and using a low lid may cause turbulent air flow into the carb.

I have heard rumors that there is a drop base that has a bigger drop, but have never seen one.

[RedSnake351]

Originally Posted by mr0077

This means that you can run an Extreme lid with a 3 1/2" element, a 3" with a dome-top metal lid (a flat or low-rise lid will also hit the air horn), or you can mill off the air horn to use a flat or low-rise lid or the Extreme top. Consider that milling the air horn with this base and using a low lid may cause turbulent air flow into the carb.

Thanks, Ken, interesting reading. I have been playing around with trying to find the ideal filter set up for the last 18 months because of very tight hood to carb clearance. When I first got the car it only had a 9" diameter by 2" high element and I always got a gas smell while driving the Cobra. I talked to an engine builder and after mentioning the gas smell he said it was a common problem to siphon gas back when the air cleaner top lid sits very close to the air horn/choke tower. I had a friend mill off the tower and it definitely made a difference in the gas smell. At the same time we cut another 1/4" or so off of the bottom lip of the 9" filter base and fitted a 2 1/2" high filter element. That combo improved the intake air flow and carb response.
After all that, I installed a K&N 14" drop base filter with a 3" high element with metal domed lid, again with airflow improvement, although I noticed that the lid's edge hits the underside of the hood's scoop and chips the paint slightly when getting hard on the throttle.
Just recently bought but yet to install the K&N Extreme top, anxious to see what difference it will make in the SVO351W HO.
I'm beginning to think with all the money I spent on filters I could have installed a 427R Roush.
Ralph

[Jim Vander Wal]

I have a 14" round drop base aircleaner. This is stamped aluminum with smooth flowing curves into the the carb. I can't check it as I'm traveling this week but I would guess that the top of the element is the same height or slightly higher than the aircleaner mounting surface of the carb when using a 3" tall element. I really like this product.

I bought it from CV Products in NC. About $50 w/o element.

http://www.cvproducts.com/cv/

Their website is a pain to use, I'd just call to get more info. I think that it is listed under the CV Products collection but didn't wade through all of the pages looking for it.

Jim

[thudmaster]

I got my drop base from a guy who races circle track. I looked at his freinds cars and they have them also. It makes it so I can run the victor jr. and big carb and still be under the scoop.

[Randy Rosenberg]

I'm happy with my drop air cleaner - I got it from Universal Spinners: http://www.universalspinners.com/autoparts.html