what size carb ?

-
73-340

73-340

Well-Known Member
Joined
Apr 3, 2010
Messages
153
Reaction score
0
Location
Delavan,il
i got a 340 9.1, edelbrock rpm heads, crane 1.5 roller rockers, edelbrock torker intake, crane 470-270 cam. 727 w/2200 stall and 3.21 gears, i plan to run 750 holley vac. secandarys. is this a good choice? i have on hand a 750 edelbrock , and a 600 holley vac. secondarys. i have had the 750 eddy on before and it run fairly well, just want some other opinions. thanks.
 
750 Holley will be good. Will be better if you get the 4150 conversion kit and put jets in the rear. But it will work good as is.
 
If your looking just for more power, putting the Edel 750 back on and getting 3.55 gears to replace the 3.23 might be more noticeable. Depends how often and far you drive on the freeway. If like never, 3.91 are better still.

The 750 holley should make a few more hp over the Edel, maybe up to 20 hp.

3.91 gears might gain you a half second in the Q mile
 
IMO, the engine package could use a dual plane instead of the single plane torker. The cam is small.
 
rumblefish360 said:
IMO, the engine package could use a dual plane instead of the single plane torker. The cam is small.
Click to expand...

X2. The original eddy Torker is a dud. I bet a RPM or RPM Air-gap will perk it up quite a bit. With no more cam and compression than you have the smaller carb should work fine but you can try the 750 Holley just to see if it likes it. They are fantastic carbs.
 
fishy68 said:
X2. The original eddy Torker is a dud. I bet a RPM or RPM Air-gap will perk it up quite a bit. With no more cam and compression than you have the smaller carb should work fine but you can try the 750 Holley just to see if it likes it. They are fantastic carbs.
Click to expand...
i think we were typing at the same time.
 
how about this one. ebay $170

intake.jpg
 
73-340 said:
how about this one. ebay $170
Click to expand...

That would be a fine choice.
Look around because I am sure there are others for way cheaper on ebay.
I paid 140 for mine. They work on a magnum or an older la engine and the holes you dont use can be plugged with plugs that come with it.

for the money, you can't beat it and it's practically the same thing as the edelbrock it copies, only it's cheaper. Nothing wrong with it at all.

Again, search for more of them. I am sure you can pay less. Every bit you can save on that can go toward something else. A little here and a little there can save you bigtime in the total cost of what you plan to do.
 
Don't buy that intake off of e-bay! I bought the polished version of that one. It is a Chinese knockoff. Had a major vacuum leak under the intake, burning oil like crazy! The surfaces that match up with the head ports were machined at a wrong angle. I got an intake from a '72 340, It works great.
 
If you have the original 340 intake, use it. There's not ONE SINGLE aftermarket aluminum spread bore intake that can outflow it. NOT ONE. Well, ok, maybe one. The Offenhauser, but it's like 350 bucks. Those intakes flowed way better than they led on. You can actually do a bit better than your 73 model. The 1971 340 intake is the best, because it did not even have the EGR port bulges in the plenum. The 1972 had the bulges, while the 1973 was actually machined for the EGR passages, but came from the factory with plugs in the plenum holes. Since the 71 has a completely flat plenum bottom, it flows the best of the three.
 
the convertor kinda makes up for the lack of gear, not to say the cam is really big or anything...but maybe you should run the 600 vac sec for now with a dual plane like the other guys are saying, unless you want to make more power at 5000 up rather than making it as snappy as your combo and gears will allow down low.
 
what if i went with a thermoquad and the stock intake. TQ 9055s. more streetable and nice kick to it !!

340 intake.jpg


thermo.jpg
 
Thermoquads work great when their right but they are more complicated to work on. Lots of small parts. Plus they have the problem with the phenolic bowl cracking and fuel wells leaking. As long as you get a good one it's hard to beat them.
 
I'm not sure about the Offy intake. At $350 (or so) I'd rather look at the Action plus by Weiand as a better part than a OE 4bbl iron intake. Being that the cam is small the OE iron will be fine.

I agree with Fishy on the T-Q. Keep it cool with the correct THICK gasket.
The pictured T-Q, IMO, would be the wrong T-Q to use. It maybe doable though. I'd try it just to see. The earlier units with a lot less vacuum hook ups is what I would look for. Also, the larger primary T-Q, not the small primary T-Q.
 
rumblefish360 said:
I'm not sure about the Offy intake. At $350 (or so) I'd rather look at the Action plus by Weiand as a better part than a OE 4bbl iron intake. Being that the cam is small the OE iron will be fine.

I agree with Fishy on the T-Q. Keep it cool with the correct THICK gasket.
The pictured T-Q, IMO, would be the wrong T-Q to use. It maybe doable though. I'd try it just to see. The earlier units with a lot less vacuum hook ups is what I would look for. Also, the larger primary T-Q, not the small primary T-Q.
Click to expand...

If the Action plus is a spread bore,then yes, use that unless your budget doesn't allow. Also, the Thermoquad you have in that pic is NOT a good one. Chunk it. It's an emmisions era carb...although technially, all of them were, that one is worthless as a performance carburetor. Also,I have been building Thermoquads almost thirty years. I have never had problems or seen problems with the plastic bodies cracking....unless it got dropped, or installed incorrectly. What I have seen regarding the plastic bodies is, they can warp from under hood engine heat. In fact, that's the reason they got a bad rap to begin with. But, in aperformance application they work well. The emissions era cars the Thermoquad came on had very high under hood temps due to catalytic converters and lean burn systems. THAT'S why so many of them warped. In performance applications, keeping things cool is important, so they rarely give problems. Also, regarding the fuel well leaking. That is a problem with the thermoquad, but easily over come. Simply use a good gasoline resistant epoxy (all of them are not) and remove the well bottoms. Clean them up REAL good. then, wipe the edges with denatured alcohol and let them air dry without touching them. Apply the epoxy to the edges of the well bottoms and the edges of the carb body, assemble and let dry. You'll not have one more problem with all that. Lastly, you can go to David's site: http://www.thermoquads.com and get and the info you need regarding tuning. he even has information there regarding the best carbs to use. They are really awesome beast carbs when they are built and tuned right. They are very hard to beat on a street or even some race applications.
 
You must log in or register to reply here.
-

Back
Top