Carb for my 340 ?

[StevieP]

Just got my 1970 340 rebuilt ! It has 40 over forged pistons, hydrolic lifters,X cast heads, and a cam that kicks in at 1500rpm and tops at 5500 rpm ( Comp Cam I think don't know the numbers ) I put an Edelbrock Air Gap Intake on it and the guy at the motor shop tells me to go with a Holley 600cfm but Edelbrock recomends 650 to 750. It going into a 69 Barracuda 4 speed trany 8 3/4 diff with 3:55 gears, I don't plan on racing it, maybe once down the 1/4 a year type of thing but mostly a daily driver. What do you guys recomend for a carb

Steve

[blueduster340]

How about a Road Demon? Lots of people seem to like the Demon carbs. If I had enogh money I'd buy a 750 Speed Demon to put on my 340 but I'm probably going to go with a Holley 3310 750.

[dwc43]

The 600 is wayyy to small. You need at least a 750. I would use the stock 800 cfm thermoquad if you want to see some real performance from it. We use the tq's on all our race cars when the rules allow. THey fall off a bit when we have to switch to a holley.

[rumblefish360]

They might have suggested to use the smaller carb for throttle response and mileage reasons. Since your not really geared for the strip, a small carb will deliver well. The larger carb will give only a few more ponys up top.

DW, you need glass my freind. Re-read his post and tell me what intake he is running. A squarebore right. No choke well right.A T-Q would be a little hard to hook up as compared to a bolt on unit.
Silly boy

ooops, forgot the recomendation, ......whatever your OK with at 600 cfm to 750 will be fine. Edelbrock or Holley, it's really your choice.
I have had good luck with both carbs.

[MoparMarcIdaho]

A spread bore carb usually does better on the street because the smaller primaries make better vaccum at lower Rs.625 CFM is more than enough for street use.How often will you have it stomped?Once a yr at the track and the rest of the time you want best mileage and good drivability.Every car is different and I would try some different ones to find what works best for you.

[MY340]

I'd recommend 3 choices all having there own advantages

1) New Edelbrock 650 cfm AVS or Carter AFB #9636 625 cfm, not sold new anymore but you can find nice used/rebuilt ones for around $125 or less, easy to tune and can be modified.

2) 650 cfm Speed Demon, pricey but very good performance, good street strip carb. tuning and quality issues though maybe

3) 800-850 cfm Thermoquad, rebuilt ones go for around $150 or less, great street performance, probably the best MPG, can be modified, you will need a 3/4" adaptor though and with the Airgap manifold hood clearance will be an issue.

If you can rebuild the AFB and TQ's yourself you can pick them up for less than $50. That's what I do and them sell them for $100-$120