What carb for my 340 build?

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RustyRatRod said:
What?! I'm shocked. I figured you be all for EFI.
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Seems like the "best" current bolt-on EFI's are still iffy. Friend works in high end shop that uses EFI on most builds. Last one was simple no-brainer build. Way overkill engine shop and Holley Sniper was not right on dyno. Holley was even present. Holley sends out another new unit and it worked. But still nothing impressive at all on dyno.

I'm sure when the magazine article is published, the EFI issue won't be mentioned. :rolleyes:
 
autoxcuda said:
Seems like the "best" current bolt-on EFI's are still iffy. Friend works in high end shop that uses EFI on most builds. Last one was simple no-brainer build. Way overkill engine shop and Holley Sniper was not right on dyno. Holley was even present. Holley sends out another new unit and it worked. But still nothing impressive at all on dyno.

I'm sure when the magazine article is published, the EFI issue won't be mentioned. :rolleyes:
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That's how it was when I worked with Matt. He loves that chit. Puts it on every build he has full control over......and there are a lot of those. Go figure.....but in middle Georgia there's a lot of 100K plus builds either runnin around or shoved in somebody's garage. And every one of them I've seen him do there was "something" still not quite right about it when it left. As of now, I remain "unimpressed". Regarding Vixen, I've actually had several people make the remark that even some EFI cars don't run as smoothly as she does. Imagine that. A 56 year old car. lol
 
Hey guys I think that I've got all the pieces together now, flow numbers on the heads and Cam's been ordered from Racer Brown. Here's a quick rundown of it all;
- 340 .030 over
- 10.5-1 compression
- W2 heads w/ valve job & bowl blend - 263CFM
- MP single plane intake manifold
- Headers
- 4 speed
- 3.91 gears
- Racer Brown cam, 242 @ .050, 542 lift, 276 duration, 106 separation

I'm decided to go without a choke so just need to sort out what size carb, a quick comparison of the Holley Street HP carbs (or QF Street Q line) reads the following but I'll after some help from you gents sorting out the numbers. I don't have a great understanding of the numbers so advice is greatly appreciated.
650 carb, 69 Primary jet , 75 Secondary jet, 1.250 Venturi, 1.688 Throttle
750 carb, 77 Primary jet, 84 Secondary jet, 1.375 Venturi, 1.688 Throttle

Thanks for the help guys!
 
340MPR said:
No I'll only have the car on the road from May through to the end of September. They don't clean the sand off the roads from winter until mid April and October is to hit and miss to keep the car insured so no the car will only be fair weather driven.
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That's exactly what I used to do. But in the off-season I stuffed a 318 into it and still had a lotta lotta winter fun.
 
340MPR said:
Hey guys I think that I've got all the pieces together now, flow numbers on the heads and Cam's been ordered from Racer Brown. Here's a quick rundown of it all;
- 340 .030 over
- 10.5-1 compression
- W2 heads w/ valve job & bowl blend - 263CFM
- MP single plane intake manifold
- Headers
- 4 speed
- 3.91 gears
- Racer Brown cam, 242 @ .050, 542 lift, 276 duration, 106 separation

I'm decided to go without a choke so just need to sort out what size carb, a quick comparison of the Holley Street HP carbs (or QF Street Q line) reads the following but I'll after some help from you gents sorting out the numbers. I don't have a great understanding of the numbers so advice is greatly appreciated.
650 carb, 69 Primary jet , 75 Secondary jet, 1.250 Venturi, 1.688 Throttle
750 carb, 77 Primary jet, 84 Secondary jet, 1.375 Venturi, 1.688 Throttle

Thanks for the help guys!
Click to expand...

With the 4 speed and the 3.91’s you can use the 750. The only difference found is the 750 is about a hundred bucks more. At least where I looked. If you want to save a C note use the 650. If you have a spare C note then the 750.
 
I know this is an older post, but I'm keen to find out which carb the PO used in the end.

I have a mild 340 with a Comp XE274H hydraulic stick, my car's a 67 Barracuda, 4 speed with 8-3/4" sure-grip 3:23. I plan on running an AFB competition series 750, what do you guys think about this carburetor for this application?
 
superstock64polara said:
I know this is an older post, but I'm keen to find out which carb the PO used in the end.

I have a mild 340 with a Comp XE274H hydraulic stick, my car's a 67 Barracuda, 4 speed with 8-3/4" sure-grip 3:23. I plan on running an AFB competition series 750, what do you guys think about this carburetor for this application?
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So you already have the Carter style 750?
If you do, run it it’ll be good.
Otherwise, a Holley would be just fine as well. A bit better in tunabilty. Something like a Brawler.

A 750 will shine better on the top end. I wouldn’t go past a 750.
 
rumblefish360 said:
So you already have the Carter style 750?
If you do, run it it’ll be good.
Otherwise, a Holley would be just fine as well. A bit better in tunabilty. Something like a Brawler.

A 750 will shine better on the top end. I wouldn’t go past a 750.
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Hi rumblefish360, yes I have a AFB Comp Series 750 that I've rebuilt recently. I also have a rebuilt Holley 750 vac/sec that may work well also. Thanks for your comments.
 
yellow rose said:
Unless this is a street only car the choke is useless. The choke is the single biggest piston ring killer there is. These engines only need a very rich mixture for the first 10-20 seconds after fire up. Any longer than that and you are using excess fuel that does nothing but wash the oil off the cylinder walls and increase ring and bore wear.
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Old post I know. I guess pumping the carb multiple times to get it to run without a choke is not washing oil off either. My only issue with electric chokes is how fast they come back on when the car is still warm. Divorced chokes definitely do it better there, but are slow to come off when the car is really cold. Later 70's models had the divorced choke with an electric element to speed up that come off.
 
superstock64polara said:
I know this is an older post, but I'm keen to find out which carb the PO used in the end.

I have a mild 340 with a Comp XE274H hydraulic stick, my car's a 67 Barracuda, 4 speed with 8-3/4" sure-grip 3:23. I plan on running an AFB competition series 750, what do you guys think about this carburetor for this application?
Click to expand...

I went with a Holley 750 DP without choke
Holley 0-82751SA 750 CFM Aluminum Street HP Carburetor
I’m happy with the carb and also glad I went without a choke as now not having one I can backup that they aren’t needed (at least for fair weather driving). I broke in my motor on an engine dyno and jetted it down one size, other than that so far it’s been a great carb.
Mike N.
 
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