Hey guys,

I just got my '73 sedan running last weekend. I bought it from a kid for $150 (u.s.) and he didn't know why it didn't run. All I did was fix a fuel leak and put the plug wires in the right firing order. (he had them going 1-2-3-4) and it runs perfectly. No smoke, no knocking. I am very happy with it. I was going to put in a rotary, but now I am going to leave the A12 in there and tinker with because it runs so well. I was wondering what the stock cfm carburetor is on it if anybody knows. I was also wondering if anyone has ran a 2 barrell GM carb. I can't afford webers. Thanks.

Sounds good. Your's is the 2-dr sedan (Deluxe)? Where are you located?

I don't know what the CFM is, but it's probably around 200. It's definitely the limiting factor of the stock engine.

If you can find a wrecking yard with older cars, the early-80s Ford 4-cylinder (Mustang, Granada, LTD, etc) have the Weber 32/36 on them (it says "Holley" or Fomoco on them).

I am located in Missouri. I do not know if it is a deluxe or not. How do you tell? I will definately look into the weber style on those early fords. Do you think something in the 500 cfm category is too big with a better flowing exhaust? How much cfm do those webers flow? Thanks for the help.

Hey Ralliarton18s,

ddgonzal knows tons about dats he can probley answer the question better, I think the Deluxe - Sedan is like the one in his avatar pic and otherwise it would be a Coupe or Fastback model.

Cool, thanks!!

I think it is the sedan deluxe then because it looks just like the one in his aviator. I am so ready to drive the datto but I have to put some floor boards in it first, and seats for that matter. LOL. Missouri weather was hard on it I guess.

Yes, the US 2-dr sedans usually (if not always) have the "Deluxe" badge on the c-pillar. The only other US model was the Coupe (fastback).

500 cfm is good for about what, 250 hp? No way a feasible A12 can make that kind of hp, not even if turbocharged. The Weber 32/36 I think is 280 cfm and is large enough for a 1200cc engine. A 32/36 is often used on 4.2-liter jeeps!

If you want the 'best' setup for an A12, you don't want tons of CFM, but a set of four throttle bodies is the way to go, for example:
- twin 2-barrel Weber sidedrafts (smaller ones)
or
- fuel injection from TWM

Quote: If your 1200 engine was worked over to the max, Was capable of 100% volumetric efficiency all the way up to it's unlimited max RPM, it would need to spin at 24,000rpm before it taxed a 500cfm carb. Even with a 250cfm carb, it would need to spin at 12,000rpm to wory it.

The formula that i used is,.. Cubic inch displacement [72 c.i.] X RPM / 3456 = theoretic CFM at 100% VE. This last figure [3456] takes into acount the fact that it takes two revolutions to draw in the rated capacity of the engine.
With a more normal Volumetric Efficiency of say 90%, in a race engine at max rpm, the figures become even more rediculous.

At 100% VE, at a more realistic 6,000rpm, the 1200 [72 cubic inch] engine theoreticly swallows 125 cfm of air. At 8,000rpm, it's 167cfm. Hell, an old Stromberg 97 from a mid 30's Ford V8 flows only slightly less than that.

The two most common sins in modified street engines? Overcaming, & overcarburation.