If you are using one of these type air cleaner bases - stop, and throw it away

I use an Allstar base and Wix Racing 3-1/2” filter. Seems to work well:

 

Larry, I would have to measure the base drop. Yes on the filter and SPX. I never liked the base the OP posted that lost all of the power, and I’m not a fan of the L88 one either.

 

That Wix looks good. Only $10 more than the Allstar on this ebay seller... I'll try one out when mine gets dirty.
https://www.ebay.com/itm/373257552324

 

1-3/4” No part number stamped.

 

If these ebay guys are getting these prices for an original L88 cleaner lid & base, I should sell mine and buy a Corvette Central aftermarket.
https://www.ebay.com/itm/333140908290

 

I used the L88 base and a k&n type of chrome lid on my 455 because of good clearance issues and when chassis dynoing it I did back to back runs with and w/o the assembly. It lost 1hp with it in place, 374-375 rwhp. That was with a 3.25 or 3.5 tall element too.

 

I'm running that same base on a Holley 750", 455' in a 71' Buick Skylark. To check for hood clearance I used a bead of toothpaste around the outer top edge of the breather. The weld on the underside cross bracing of the stock hood dipped into the toothpaste when I closed the hood gently. I''ve used the Edlebrock triangle breather. The carb will suck the foam right into the engine. I quit that in a hurry! What are the best options? I believe I went with a 2'" filter element..

 

I don't have a 455, but with the real L88 base, 2" tapered spacer on top of a dual plane & 3"air cleaner element, I had all kinds of clearance to the GS hood. Could even run a 4" filter but that was cutting it close by abt only 1/2" to hood bracing.

Real or replica L88 bases have a full 2" of drop.

 

ON a related note, a week or so ago I had the opportunity to test one of those K&N filter tops, along with a flat air cleaner base, and a 2" element.. we believe that in conjunction with the shorter 1000 cfm Holley 4 barrel throttle body, this would fit under the hood of a GS, even with the SPX intake.

In dyno testing, we tested it first with a carb and distributor, before we went to the efi.. and after we had got a good baseline with a 1000 HP, I stuck this short air cleaner on top of it, figuring no way it would work.. like many of you, I had heard horror stories with these pro flow tops..

Here is the motor with no air cleaner lid on it.. for a baseline..



And then we stuck this on it.. no other changes..



I figured it would never work, remember we were going to use it for an EFI throttle body, with no metering stuff for this top to screw up, like this carb has..

here is what it made with the above setup..



Surprising... 6-8 numbers, what I would expect with any air cleaner...

Another situation that shows the importance of testing, either track or dyno, vs hearsay or assumptions

JW

 

Well this 3-1/2" filter looks impressive. You even get a performance decal, gotta add h.p.
Clears bracing by 1/2" in very front. 3/4" on sides. Still can run the 1" tapered spacer. The SP3 took up some room compared to the D/P.

 

That filter setup that Jim posted looks identical to what I run on one of my cars due to very limited hood clearance. I also ran it with a carb then later converted to FAST XFI and kept the same filter assembly. I also did numerous pulls on the chassis dyno with and without for the carb and with and without for the XFI. You always gotta know for yourself.

 

And I wonder what effect a flat hood sitting right on top of it has?

 

If the top is too close to the carburetor,you will start to see changes. Even if the filter top can pull air,it still needs to be up off the carburetor in order for the air to get direction. Anything with a scoop or cowl hood will benefit further by having an air pan to seal it to the hood. I’ve seen as much as 3 tenths difference just by doing that.

 

Something to test in the car for sure..

JW

 

Did you ever try a ram air set up

 

The ram air setup with the hoses to go under the bumper or headlights? No.
One of my cars is a 72 Cutlass with 442 ram air hood. I have used that car for a LOT of r&d. I have a filter top on that due to having no room under the hood. I literally have scuff marks on my spinner/wing nut,so it’s right there. I played around with different filters and bases,making note of what improved and what didn’t. That particular setup does NOT have ample room between the lid and the carburetor. It’s less than an inch. The filter top helped,then I made an air pan and sealed it to the hood. Then it really picked up. I did do a few dyno pulls with the air pan and no filter vs the air pan with a filter,and it made the most without,which I expected in that situation,but i will not drive or run my cars down a track without a filter.

 

Thanks Brain I have a spectra set up with hoses and funnels under the bumper I see by this thread i have to change to the allstar base no tracks with in 130 miles of me