Carburetor for 273
- Thread starter DFM
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Just for educational purposes I would like to know that myself.
i'll start off with: well it depends...
is it stone stock? how do you drive it? are you after thrilling jump off the line performance or something more mellow with maybe an eye toward some type of fuel economy? what do you currently have? what's your budget? what's your skill set tuning wise?
an easy and obvious choice would be the edelbrock 500cfm AVS 2.
in reality anything from 500~625 would fit the bill perfectly, and there's several options in that size range.
is it stone stock? how do you drive it? are you after thrilling jump off the line performance or something more mellow with maybe an eye toward some type of fuel economy? what do you currently have? what's your budget? what's your skill set tuning wise?
an easy and obvious choice would be the edelbrock 500cfm AVS 2.
in reality anything from 500~625 would fit the bill perfectly, and there's several options in that size range.
I ran a 600 Edelbrock on mine. I machined the secondary holes on the intake so it would work. You can do the same with a spacer I hear. You also have to use a different air cleaner base.
Right now have a 600 on it. Have just a little hesitation when I first hit the gas . But moves really good after that . Thinking about changing the pump accelerator. Then looking at the jets and the step up springs .
Dartsun
Mopar Dude
I'd say the Edelbrock 500 AVS 2 I wish I had one on my 273 instead of the Edelbrock 600 AFB.
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I have an Edelbrock 500 AFB in the for sale section if you might be interested.
Bob67Barracuda
Well-Known Member
[SOLD] - Carb: Carter AFB 4-bbl 4295S
This carb was pulled two years ago from a running 318. It's been boxed in the garage since then. $125 plus shipping. I'm in St. Paul, Minn.
www.forabodiesonly.com
This Carter (now sold) was a good performer when I had a 318 dressed up like a 273.
lemondana
BlackDart
I have a 1050 Holley 3 barrel that would be perfect
.
.I have a 1050 Holley 3 barrel that would be perfect
stroker402
1968 dart GTS convertible
my 273 is not that radical and I run a holley dp 700.... I tried carters and holley carbs of all different sizes.. my engine loves the holley dp 700 .. I give it what it wants .
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I have a 1050 Holley 3 barrel that would be perfect
The best is an original AFB, then a TQ, then a QuadraJet, then a small AVS. As for new carbs, I have been wanting to try a Street Demon, but have not got around to it. Edelbrocks should work, I hear good things about an AVS 2.
If you are running an automatic, you might just change the Accelerator Pump Nozzle to a larger size like they did on the originals.
DFM,
Have you checked the basics:
- float level
- engine idling, in gear if auto, metering rod covers swivelled slightly so that the piston tops are visible. Pistons should be down, not moving; pistons moving can cause flat spots; require softer springs.
Have you checked the basics:
- float level
- engine idling, in gear if auto, metering rod covers swivelled slightly so that the piston tops are visible. Pistons should be down, not moving; pistons moving can cause flat spots; require softer springs.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Normally aspirated cfm baseline is;
(CID x RPM/3450) x VE = cfm
Example-1
(273 x 5000)/3450 = 396cfm@100% efficiency
396 x 85%, on a hot engine , = 337cfm
Example-2
With a 2bbl compression ratio and cam etcetera, say at 70%, shifting at 4400, this maths to ~244cfm.
Example-3
a 600 is good to 7600@100%
Example-4
I'd put a
small Thermoquad on it, with an old "DualPort"
Just saying.
(CID x RPM/3450) x VE = cfm
Example-1
(273 x 5000)/3450 = 396cfm@100% efficiency
396 x 85%, on a hot engine , = 337cfm
Example-2
With a 2bbl compression ratio and cam etcetera, say at 70%, shifting at 4400, this maths to ~244cfm.
Example-3
a 600 is good to 7600@100%
Example-4
I'd put a
small Thermoquad on it, with an old "DualPort"
Just saying.
This is why I never use those calculations. A 273 will run the best with a 750 cfm Thermo-Quad, more, power and better mpg. No way I'd run a restrictive intake manifold on a 273 like an Offy dual port or Edelbrock sp2p or Streetmaster.
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It's been my experience that accelerator pump linkages on Carter/Edelbrock carbs are a little finicky.
All of mine needed adjustment and most needed more pump shot/earlier pump shot via the linkage.
Eventually all of them behaved normally without any additional mods.
I've also noticed the pump squirter nozzles tend to get plugged and aren't super easy to clean out.
However they are super easy to get to.
All of mine needed adjustment and most needed more pump shot/earlier pump shot via the linkage.
Eventually all of them behaved normally without any additional mods.
I've also noticed the pump squirter nozzles tend to get plugged and aren't super easy to clean out.
However they are super easy to get to.
Frank Mopar
Well-Known Member
500-600 vacuum secondaries.
Dartsun
Mopar Dude
If it runs best with a 750 thermo why didn't the factory put them on it?
The carb didn't exist back in the 60's when the 273's were made.
Dartsun
Mopar Dude
Google tells me thermoquads came on engines in USA from 71-74. Pretty much when engines lost compression.
273s were all done by 69, High Performance 273's were done by 1967. I have tried almost every 4 barrel carb, and a lot of intake manifolds, on a hot and almost stock 273, and I can tell you nothing is better than a TQ on a 273. The original AFB is better than most, almost like it was calibrated just for it. I tried a Holley, and it worked OK, I'm just not interested in having to work on a carb all the time. I do not like them.
71 was still good compression, the TQ just works and it still passed emissions, that is why it lived on to the end. It is also adaptable to use on a very wide range of engine sizes.
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