Holley 2-bbl on 273

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Claydart

Claydart

MOPAR to the very bones
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Hi, I was wondering if I would get better performance out of my bone stock 64 273 if I installed a Holley 2-bbl 350 cfm on it? Any ideas? I don't know what the stock carter 2 bbl has for a cfm rating, and can't seem to be able to find the ratings anywhere.
 
You could. It would be about the right size. Not a huge fan of the adapter to make it work though.
 
If it's a Carter BBD, it's probably 265 CFM rating, the 318 BBD was 285 CFM. A 383 and 400 two barrel had a 365 CFM BBD with a bolt pattern between the small BBD and a Holley or Autolite two barrel. A better choice if your hellbent against swapping manifolds or don't have a manifold available for the odd angle 273 bolt pattern is a four barrel adapter and a 390 CFM four barrel. Your cruise economy and response will be better cruising around on the 195 CFM primaries.
 
This engine is the two barrel 64 273. just looking at the carb. on this thing, and thinking that the carb. on my lawn tractor is bigger. I have a Holley 350 cfm carb. that was originally on my other Dart with the 6=8 Clifford package. The package came with a four barrel, but the PO changed it out to a two barrel because he thought that the four was too much. So he gave me the four barrel also, when I bought the car from him.
 
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I would like to be able to use this carb on my 273 2-barrel manifold. So are you saying that it would not fit or that I shouldn't bother?
 
Bores and bolt pattern are larger on the Holley, it will take an adapter. If your going to have to buy an adapter, you’d be better off to buy a four barrel adapter and use the four barrel from the \6, provided it’s reasonable. What was the four barrel from the six?
 
Edit: The four to to barrel adapter you have on the Clifford intake may work if it has the slots for the two barrel bolts. Use what you have.
 
The manifold on my 273 is a two barrel manifold. Will the Holley 2 barrel fit on that, or will I need an adapter for that carb on that manifold. Or will any 2-barrel fit any 2-barrel manifold. If it will fit, I will use the 350 Holley on the 2-barrel manifold on my engine now. And not have to find a 4-barrel manifold that fits my 64 273.
 
It sure looks like it will have a higher CFM than the BBD that is on my engine right now.
 
You'll need an adapter, this will do it. Mr. Gasket Carburetor Adapter Kits 1937MRG
You'll have some improvement in performance as well as over the counter access to jets and power valves if you need to tune it. But, if you have a small four barrel on hand, you would have improved driveability and mileage compared to either two barrel. The four to two barrel adapter on the Clifford \6 manifold can be turned upside down on your present two barrel intake if it has the slotted bolt pattern for the different two barrel sizes.
 
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I also have the 4-barrel that was supplied with the original 6=8 kit from Clifford, but I don't know what size it is. I will run the numbers off of it to find out what size it is.
 
Your 273 by the math, and assuming a VE of 70%,which is probably overly generous a VE; wants
(273 x3600)/3450 x 70%= 199cfm @3600rpm,
at 4000 maybe 222 cfm....
at 4500=249cfm.
If your engine is physically capable of pulling in only 249 cfm, there is no point in installing anything bigger. especially if it costs you money to install it..
However 2bbl carbs are rated different from 4bbl carbs, but in this instance I think it's nearly moot.

I had a 340 2bbl once; with a teener carb,,intake, heads, and cam, awesome lil combo in an early-A wagon.

If you do this swap, make sure you do some before and after time trials, to see what it was worth.

You'll have waaay better results with a higher stall TC and/or bigger rear gears.
 
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What is the CFM of one of those little BBD carbs like I have on my stock 64 273?
 
Like said, good gears and convertor, makes all the world difference in seat of the pants feeling power. Yes way easier to bolt on a four barrel and great to hear the other barrels kick in. No doubt, vac. advance will make some difference.
 
Well, I just watched a video about all types of carbs by Uncle Tony and it was extremely informative! I learned more about carbs in a half hour than I would have tinkering around for forty years.
 
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