Carb upgrade on 65 dart 2bbl 273

[65VERT]

Looking to upgrade from a 2bbl to a 4bbl on a 273. What are pro's and con's with this upgrade want to keep completely stock otherwise.Any suggestions on manifiold (Brand) and carb. I was looking at edelbrock manifold but not sure on a carb. Would a 4bbl carb from my local parts shop HolleyII Stromnberg ,Champion be compatiable with edlebrock ? Any suggestion and guidance would help. Thanks

 

[cavemanmoron]

if your not going to upgrade the cam, and add dual exhaust
i would suggest leave the 2bbl on.


I would suggest add the dual exhaust before adding a 4bbl,
this will be a noticable improvment.

I have a 64 Valiant, 273 2bbl, and had a 67 Valiant,
273 2bbl, with both cars, I added electronic ignition, and Dual
exhaust with Turbo mufflers.

The '67 car, I was drag racing at the local 1/4 mile, and i got
aprx 7/10ths quicker adding the duals.

My local Midas shop did a nice job, going from the stock manifolds,
then going to 2 1/4" pipe, thru the mufflers,
and out the back.

I have had Mopar cars since 1976. Tried adding a 4bbl on a 360
2 bbl car years ago. I put the 2 bbl back on, and was happier.

A 4bbl on an engine that can't breath, and use the fuel is asking for
problems.

The 2 bbl cam will not make use of the fuel, and the compression,
on the 2 bbl is only 8:8-1, vs 10:5-1 on the 273/4bbl.

Lee/cavemanmoron

Yes, I have a 4bbl on my engine now, but its not stock. ;)

 

[Thrashard340]

65Vert, which Edelbrock manifold do you plan on using? Do you want manual or electric choke? Something no more than 600 CFM, by Holley(0-1850S) or Edelbrock (1405) would be a good starting point. These are manual choke carbs. They are also squarebore flange. So if you are using Edelbrock manifold #2176, which is suggested as a stock replacement, then you will need a 4 hole adapter from squarebore to spreadbore. T340

 

[cavemanmoron]

Another thing, if the 273 is a 1964/65 engine, the intake has a 2 year
only pattern, the intake for the 1964-65 engine is hard to find.
{read not cheap, from a junkyard. }

A 273 has very small ports, if you do decide to go with a 4bbl,
be sure to use a small port size intake, not a 340/360 newer style intake.

The 273 4 bll was an AFB, if I recall it flowed aprox 525 cfm.

Someone here on the site did have an Old intake for sale.
It is sold, they asked $120 for it.

Another one, Offenhauser. Captainkirk has for sale.

http://www.forabodiesonly.com/mopar/showthread.php?t=10331&highlight=intake

 

[Thrashard340]

Ditto to what cavemanmoron said...if you plan to do the intake, upgrade to dual exhaust.

 

[redfastback]

IMO, choose the edelbrock 500cfm and just the regular performer manifold. you will get better gas mileage when putting around town on just the primaries, but can open it up a bit for some pep. my 64 dart gt 273/2bbl 4speed had a 68 340 4bbl manifold and a 68 avs and it picked up a bit for a stock 2 bbl motor. and yes, dual exhaust will help it breath better. more coming in means more has to go out.

 

[65VERT]

Thanks alot for all the info I do have dual exhaust so it looks like a done deal to move foward with the project.
Negotiating with captainkirk on the Offenhauser. Hopefully all goes well. I'll post with a update Thanks again to all who responded.

 

[rumblefish360]

Good luck with the project. The intakes aren't at your local store and make it hard sometimes. I've only seen one hanging on a wall at a speed shop once. Never bolted on. Engine owner purchase mistake. Sat for years.

On the carb, a 500 cfm 4bbl is what I also agree with. Though I do believe you'll find better mileage because the 2 bbl is rated differently than the 4bbl. 1/2 of the carb is what you'll be driving on.
Tune the primarys well and it'll be sweet. IMO, I'd do an electric choke.

 

[65s]

I have a '66-67 273 Commando 4 barrel iron intake for sale. $125 takes it. Sandblasted and ready to go, unmodified all original.

I can deliver it to Carlisle if you want.

Neil