Carb Recommendations needed for my 340

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73SwingerBuild

73SwingerBuild

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Hey all,
I'm looking to get my car on the road ASAP and I figure now is a good time to get a new/rebuilt carb. The one I bought a year ago showed up with fuel in it, and it's been a year of sitting in a dusty garage, so I'm sure it needs a rebuild. The one I have is a Holley 3310 750CFM with vacuum secondaries and no choke (assembly was removed). I'm told it started in the cold and ran well, but I'm hesitant to run no choke in New England.

The drivetrain is a 340 with 9.5-10:1 compression, iron J-heads, unknown cam (told it was decently aggressive, but fine on the street), single plane holley strip dominator intake, dougs headers, backed by a non-OD A833 4speed and a final gear of 3.55:1 in the 8-1/4" rear.

Does anybody have any recommendations on a carb for this setup? I will be mainly driving it on the street, maybe some track time, mostly cruising and lighting 'em up at traffic lights. I'm told a 650CFm double pumper will work, but I'm not sure if I have enough rear gear for a DP. Also told a 750CFM with vacuum secondaries and no choke works well (which I have), but again, I'm hesitant to not run a choke.

Thanks all.
-Mike
 
I have 2 340's, one has a 650 DP and the other a 750 vac sec, both run good. I would leave the carb you have now, can always try the other when you get it running. Not having a choke will make it run rough when cold, my 340 Valiant is cold blooded!!
 
Hi,
I live in RI and have a 66 Barracuda with a 360 modified. I'v had a 3310 and a 600 holley on it with no choke. The car runs quicker with the 3310 but better overall with the holley 600. I prefer the 3310 but the 600 is on it now. Both carbs run OK without using a choke. It just takes a little longer to warmup. I run the car from April to Nov.
 
I have a 340 demon with an unknown cfm demon carb and it needs replacement. It also has iron J heads and an unknown mild cam. Local mopar guru claims a stock 340 runs best with a 650 cfm carb. I'm experimenting with a 750 proform...double pump with mechanical secondaries. I bought it new on e-bay for 439 including delivery. Has dual feed,double pump,sight glasses for fuel levels, electric choke, basicly everything My 950 had on a 498 stroker except 125 cheaper and it was a great carb. My thinking is in 71, a stock 340 could be had with a 990 cfm six pak setup. I understand My motor in 72 was de-tuned but it has an above stock cam,headers and I assume at least 9 to 1 pistons. It runs out quick with the demon so I hope it runs even better with the 750 proform. Good luck and I'll keep You posted
 
66340SEDAN said:
I have 2 340's, one has a 650 DP and the other a 750 vac sec, both run good. I would leave the carb you have now, can always try the other when you get it running. Not having a choke will make it run rough when cold, my 340 Valiant is cold blooded!!
Click to expand...

I'd love to use the carb I have, but I think a rebuild is in order. What does a typical rebuild cost at an average shop? I found a fully rebuilt 650DP with a manual choke for less than $200, so I am tempted to jump on that and keep mine as a spare for later/track time.
 
Both look applicable, though pricey. I'm thinking I can get my carb rebuilt for less than $150... but I'm not sure. Guess I'll have to ask around.
 
Why not rebuild it yourself ?
Rebuilding it is simple,and rebuild kits are cheap.
Put it on the bench,and start taking it apart. Take pics as you go.
Use compressed air to blow out all the ports and passages.
Set the floats,before you know it your done. No better way to understanding your carb,with the satisfaction of knowing you did it yourself.

Tip: Using a little chapstick on the bowl gaskets makes them come apart nicely.
 
Johnny Dart said:
Why not rebuild it yourself ?
Rebuilding it is simple,and rebuild kits are cheap.
Put it on the bench,and start taking it apart. Take pics as you go.
Use compressed air to blow out all the ports and passages.
Set the floats,before you know it your done. No better way to understanding your carb,with the satisfaction of knowing you did it yourself.

Tip: Using a little chapstick on the bowl gaskets makes them come apart nicely.
Click to expand...

Thank you for the heads up. If I end up buying a new carb, I'll have to experiment with this one. I'd definitely like to learn, and I feel like it's something that I should be able to comprehend (4 years of engineering classes should start paying off any day now...), but I have so much on my plate now that I don't want to be starting any new projects.

New England Summer Nationals are approaching quickly. My goal is to be there with the 340 running and paint shining... we'll have to see if I can meet that goal.
 
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