Hi all,

I am planning on replacing a 1" aluminum carb spacer with a phenolic carb spacer on my 1970 440 w/ a stock intake manifold and 750 CFM Edelbrock carb. I have a couple of questions for those out there who have done this:

1. Does a stock 440 manifold use the "open" or 4- hole spacer? I think it's open, but don't have access to the car for awhile to check it.

2. Any recommendations on one that works well on dissipating heat? I see Summit sells their own model and also carries an Edelbrock brand. Any preference?


Thanks much for your help!

Use a 4 hole spacer, pick whichever you want.

Edelbrock-Carter AFB's ONLY like the 4-holer. This per their own web site. This also from my own foolish experiences.

EDIT: The trick is to get the correct thickness spacer. Years ago at a swap meet, a vendor was selling 4 hole paper gaskets 1/4" thick. I bought 8 of them, and I use those to determine which thickness my particular engine needs by stacking them one at a time until I narrow it down. Three different engines, three different thicknesses.

I bought one off ebay (tho it's only 1/2"). Best price I could find. Link to the guy's ebay store is below.

Just get a 4 hole as advised, the 4 holes line up with the 4 butterflies on the carb. For my demon carb (big butterflies) I had to open up the holes a bit but it's easily done with sandpaper.

ebay link

Thanks a lot guys! I'm glad I checked here first!

The Carter carb, AFB or AVS intake manifolds(1969 and earlier) have the four holes, the later Holley carb. intakes(1970-71) have two elongated holes, one on each side of the intake divider The later Thermoquad intakes are another story altogether I would use the open on the hooley type intakes and the four hole on the Carter type intakes

Look at shear plates also, you can get them insulated and they work wonders. Tim

Just make 1 out of wood, Hickory. Its a very hard wood. If you have a gasket you can make the spacer. Not hard to do and works great at insulating.

Insulating is one thing, but I can vouch for idle/driveability improvements with the cheap 1/2" 4 hole spacer. There are many reports of increased low end with the 4 hole.

When I put it on, I think the carb was getting a better signal and I was able to close the butterflies quite a bit. My engine has always had issues with idling as it's a big cam in a low compression engine. That's the reason I went with the mighty demon because it had the adjustable idle-eze. Adding the 4 hole really helped for both heat and carb function in my case.