Stock or aftermarket

[344speed]

Which is best putting the stock carb on or putting an after market carb on? My motor is .30 over and pretty much stock except for a small cam. I have heard that on the original carbs the bowls warped if they sat with gas in them. I am not really going for speed just the natural get up and go.

[Chryco Psycho]

I feel carbs have actually come a long way , so I would definatly lean towards a new carb over a 40 year old one , Carbs like the Proform are extremely adjustable & have fantastic response . EFI is even better but cost signifiacntly more .
 Do Not under carb I typically use 2x times the CI as a baseline so a on a 383 I  would use a 750 , 440 850 etc

[344speed]

Thanks, I just have a 340. I read through some of the other posts and gathered that a 700 Proform will do the trick? I did a search for those and only seemed to find the base plate.

[MEK-Dangerfield]

Thanks, I just have a 340. I read through some of the other posts and gathered that a 700 Proform will do the trick? I did a search for those and only seemed to find the base plate.

The problem is Proform doesn't actually make a 700 CFM carb. You can go 650, or 750. You also have to choose between a vacuum secondary or mechanical. I'm not sure your preference, but here are a couple of possibilities.

   http://www.summitracing.com/parts/PRO-67213/


   http://www.summitracing.com/parts/PRO-67258/

[Supercuda]

If your 40-year old carb is a Thermoquad, a new carb won't be an improvement, just a different carb. The phenolic resin center section of the carb would warp due to overheating, not fuel. Overtorquing fasteners into the resin would blow out the  bosses, and J-B Weld used to be included in rebuild kits to repair this common problem. The TQ is a very adjustable carb, and can be made to run as well as any carb currently available. Its spreadbore design and HUGE secondaries make it a wonderful carb on a 340, allowing gas-sipping economy and killer response and power production. Just my two cents. If you stay with the TQ, re-bush the throttle shafts.

[344speed]

Thanks all for the ideas, EFI is definately not an option. That is beyond my budget. The proforms are kinda pricy also. I had an edelbrock on it that worked pretty good but I am not sure of the size. I have heard about the bowl warpage problems on the original TQs besause of them being plastic. Since this is the first E body I have owned I am trying to head off potential problems. I have a TQ for a 4 speed that I was thinking of using until I started hearing about the problems with them I would have liked to use it just to keep it stock. Of course it would have to be rebuilt but even then if it is going to warp it will be problematic. My motor is coming out of the shop soon so in the next month or so I will have to decide which to go with. I would have thought with the new technology they would have came up with a new bowl that did not warp. I also have heard that with the TQs that they did not vapor lock. Is that true? What about the other carbs mentioned, do they vapor lock? For peformance should'ne I stay close to an 800 like the TQ was?

[Chryco Psycho]

A 750 would be fine , the TQ still cannot change the air bleeds like the Proforms can so the TQ while it is very adjustable is still not quite as adjustable as the newers carbs are

[mopar12372]

the holley street hp looks like its priced right  http://www.jegs.com/i/Holley/510/0-82751/10002/-1?parentProductId=757757  , use a(1in) this is a 2 in ,(single plane manifold   http://www.jegs.com/i/JEGS/555/15463/10002/-1 with 750 it creates a better fuel signal so it will make the carb flow more . a open spacer for a duel plane manifold (eddelbrock performer rpm) .

[344speed]

Thanks Chryco. I am convinced the proform is the way to go. I will let my wife know what I want for Christmas!

[440mike]

i am a bit stunned.
at work, i just witnessed a .030 over 1972 340, with ported iron j heads with 2.02 valves, and a small "thumper" comp cam(guy wanted the sound), original iron intake manifold, and the original 1972 340 thermoquad carb that was untouched since new, make 415 hp on the shop dyno !
even the friggin choke worked !
the thing looked absolutely stock except for the dyno headers for the session.
if you can find a guy who still knows how to "work" those thermoquads, I am a BELIEVER !

[Road_Runner]

i am a bit stunned.
at work, i just witnessed a .030 over 1972 340, with ported iron j heads with 2.02 valves, and a small "thumper" comp cam(guy wanted the sound), original iron intake manifold, and the original 1972 340 thermoquad carb that was untouched since new, make 415 hp on the shop dyno !
even the friggin choke worked !
the thing looked absolutely stock except for the dyno headers for the session.
if you can find a guy who still knows how to "work" those thermoquads, I am a BELIEVER !

That 340 sounds pretty sweet!  I've wondered about those thumper cams, are they trying to get that 70's "3/4 or Full Race Cam" heavy hitting sound like we had back then?  One of the looks I've considered for the Barracuda is nearly stock, but anything I can hide is fair game.  400+ HP out of a stock looking is pretty cool.

Later, Jim

[440mike]

That 340 sounds pretty sweet!  I've wondered about those thumper cams, are they trying to get that 70's "3/4 or Full Race Cam" heavy hitting sound like we had back then?  One of the looks I've considered for the Barracuda is nearly stock, but anything I can hide is fair game.  400+ HP out of a stock looking is pretty cool.

Later, Jim

yes,
it was a very bone stock appearing engine !
the stock air cleaner killed 23 hp, (when it was put on towards the end of the session) , but i guess the 390 hp even with the air cleaner on will move pretty good !

i guess the thumper cams don't make as much power as others, but they sure do sound cool ?

i was really surprised it could do that with the stock iron intake & thermoquad carb !

[Chryco Psycho]

typiaclly Mopar had some excellent intake & exhaust manifolds on their performance engines , some of the M1 intakes are just alum versions of the factory originals & make greaat power . the TQ is the best carter carb built & is very adjustable & not under sizd like most factory carbs were , but you have to find one in good condition with no cracks or warping of the bakelite bowl , rebuild kits are still available but the the tuning kits with different jet & rods are difficult to find

[Road_Runner]

typiaclly Mopar had some excellent intake & exhaust manifolds on their performance engines , some of the M1 intakes are just alum versions of the factory originals & make greaat power . the TQ is the best carter carb built & is very adjustable & not under sizd like most factory carbs were , but you have to find one in good condition with no cracks or warping of the bakelite bowl , rebuild kits are still available but the the tuning kits with different jet & rods are difficult to find

I've got to settle in on one target configuration and just go for it.  I have a 340 and both the original 4 bbl intake and an LD340 intake, would I be insane to go with the iron intake?  The more I hear I can reach my HP targets and remain outwardly original it appeals to me more & more since that matchs what I'm doing with the rest of the car.

Later, Jim

[Chryco Psycho]

well the LD340 was one of the best intakes of all time & painted it would look good but the Iron intake with some port work is no slouch either & if it will get you where you want to go why not use it