2 Barrel (2-5/8" Neck) Carburetor to Air Cleaner Spacer for HEI Upgrade

I replaced the points ignition with an HEI setup in my 1967 Chevy Truck.

The larger-cap HEI interferes with the stock flat-bottom air cleaner, which also lacks the 'dent' in it that the later, HEI-equipped vehicles had.

Most carb spacers and risers are made from  ABS, phenolic resin,  hardwoods, or resin-impregnated wood, as they are in a relatively low-heat area and easily formed and cheap.  Of course, more expensive items are available in aluminum, carbon fiber, and other, more exotic, materials.

I could not find a riser/spacer for a 2-5/8 neck carb or a suitable early 2-barrel with HEI air cleaner (suitable in this instance also means cheap or free), so I (finally) found the piece of 1/2-thick UHMW plastic I had 'stored in a safe place' and made my own riser/spacer.

I was halfway through before thinking about making and instructable, so bear with....

I started by using a compass to draw a 2-5/8" and a  3" circle from the same center on my UHMW (Ultra-High Molecular Weight) plastic.

I held the UHMW on top of a piece of scrap wood and 'drilled' the 3" circle with a - {wait for it} - 3-inch hole saw.

I then screwed the 3-inch circle to a cross-tie with three 2-inch screws to keep it from moving while I drilled the inner section out.

Since I do not have a 2-5/8-inch hole saw, I used a 2-1/2-inch hole saw to cut out the inner circle, and shaved it out to fit 2-5/8 with a retractable box knife.  UHMW is fairly "soft" so it was easy to do.  Just be patient and check the fit often so as to not shave off too much.  The cheap hole saws also have lots of 'wobble' so it's not a 2-1/2 inch hole, anyway.

As you can see by the first four pics, the UHMW feathers and burns/deforms if the drill speed is too high.  I knew I would have to whittle on it some to make it fit so I didn't worry too much in this project.

The finished riser works well and I didn't spend any money on it - everything I used I have had for at least ten years.  Except the truck...

I was also able to use the stock filter mount bolt.  It still has enough threads left to go up almost 3/4-inch if I had to.

The only thing I might buy is a second air cleaner gasket to make sure there is no leak between the riser and the air cleaner.

The HEI runs great, starts better, has a little more torque, and should net me a little more MPG.