Carb spacer fit info for 71'

[walkman]

This is what I have found out. I'm changing my stock 71' intake maniflod to a Edelbrock aluminum # 2101 Performer the only one that will work and fit pre 86' heads on a 270hp engine and hood clearance. There is enough hood clearance to put a 1" spacer with gaskets, (2) one top one bottom of the spacer on the maniflod. The stock gasket ( it's not a spacer) is a 1/4" thick, therefore you would be only raising the carb 7/8". The best style and material is a 4 hole spacer, ( better bottom end, idle to 4200rpm) than the open style spacer (comes on about 4000rpm) and made of phenolic resin. Plywood is very good material also, but the phenolic is made of wood with resin added. The rule of thumb is for every 10 deegres lower fuel/air mixture temp. = 1% hp. gain. That is why you don't want heat transfer to the carb. I didn't take heat readings before I started, but will have them when I finish and will share them in about a week. Any questions or comments please.

 

[RodsnRides]

I can't run the phenolic spacer on mine. I also have the Performer 2101 and run the stock air cleaner. I also installed the GM heat shield under the carb-GM part number 3969837 (old) or 10147945 (new), this has the 1/4" gasket on one (carb) side, and a thin paper gasket on the other (engine) side, with about 1/8" aluminum shield sandwiched between. This shield has a cutaway for the choke thermostatic coil and rod, I used a hole saw to make a tidy access for the vacuum port.

I noticed I have a very slight rubbing on the hood, I figured it out when I saw a slight bit of white powder (fibreglass) on my air cleaner lid, then I saw about 3/8 inch white spot on the hood, not significant, but I noticed it since the underside of the hood is black. It is the stock, flat hood.

If I went to polyurethane motor mounts, this might prevent it, but it tells me that I won't get away with any carb spacer! Just an FYI.

Rick
:gap

 

[walkman]

I put a small cookie holder made out of thin clear platisic 1" high on top of the stock air cleaner at the very front and then on the back of the air cleaner and closed the hood each time without bending the platisic, so there is at least that clearance. Removing the 1/4" gasket and replacing it with the 1" spacer and gaskets should work, total new height 7/8". The job will be complete on Sept. 8th. I will let you know.

 

[Jack]

For 2101, OE intake or other intake that have exhaust Xover ports.
If you can go chokeless or modify yours ... do this:
Cut thin (steel not alum) shims to block exhaust Xover ports on each head ... silicone those shims to each head ... then install gaskets ... then intake. Our regional Ctrack race rules specify 2101 ... everyone with a lick of sense blocks their Xover ... blocks exhaust Xover heat from coursing across & heating plenum-carb-AF charge. Just keep in mind ... street-cars' hot-air choke will not function/open unless it's rigged. Run steel ... alum will burn thru.

 

[walkman]

Great tip. I wasn't even thing about that old trick, it does work good. Thanks.