Carb advise 340 LA

[brasil]

Hello Folks...

my 340 cui Needs a "new " carb.... the engine is from 1973 the heads are the AAWJ-340 castings ( 2.02 Valves ) Cam ??
don´t know...the Manifolds are HP manifolds and the Intake is a 3512100 from 1971... ( with spreadbore pattern...but I have the 4 hole Adapter from EDE also...
Transmission is a 727 rear end 3.23 Converter stock ( @ 2400 stall )
Wanted to use the OEM 6319 TQ ...but... the carb needs to be rebuilt ( whisteling operas )...so I was leaning towards a 600 EDE ( 1405 ) or perhaps the 600 cfm carb from SUmmit ( the 4100 autolite /Holley replica )

What do you think?

Thanks for any advise

Greetings Juergen

 

[Adam]

1. Think about having the thermoquad rebuilt. they can put bushings in the baseplate to fix the worn shaft bore. If the bottom of the fuel jet wells are separating from the bowl then forget it... 2. Get rid of the adapter and get a spreadbore carb or 3. get a new intake and squarebore carb.

 

[Chryco Psycho]

I agree , the TQ is the better choice , my real question is why would you be looking at 600 cfm while removing an 800 cfm , the smallest carb I would use is a 700 cfm & Proform is where I would spend my $$ , the Eddy 1406 or1405 are awful at best

 

[Racer57]

I have an Edelbrock Thunder Series AVS 1806 650cfm on my 383 that provides good response and mileage.

 

[brasil]

@ Racer 57 I have the same carb laying around... can you give me some Info about your calibration ...jets / rods /springs ..

@ Adam what wrong with the 4 Hole Adapter.. ..I had a EDE Performer Intake on this engine... the OEM Intake is way better !!

@ Chryco Psycho do you think the 600 cfm is to small ?? I do not rev more than 4500-4800 rpm.. Proform carbs ? Never heard about.. I only know EDE,HOLLEY; TQ ; QJ; Quickfuel.....

Greetings Juergen

 

[Racer57]

Only thing changed from new was the air dam spring was tightened 1/4 turn to get better response.

 

[Adam]

IMO the adapter is just a band aid. It will allow mismatched carbs and intake to work together but the results will not be ideal. Reportedly, a four hole spacer may help low end torque but also hurts top end; also an open spacer may hurt torque and help top end. Either way is a compromise... I think you would be better off with a matching carb & manifold; especially since your correct carb is a Thermo-quad. Lastly, the money to rebuild that carb may be less than a new carb: http://www.carburetorusa.com/carburetor_usa_013.htm

Summit Racing also sells rebuilt Thermoquads :http://www.summitracing.com/parts/sum-210236/overview/

 

[brasil]

Hello Adam



thank you for your advise... I know that Summit sales those TQ carbs.... but I am afraid of getting a carb that is JUnk... Ordered a Q-Jet from Summit 4 years ago.... and the carb was....JUNK two different rods... and a base plate that was whiseling "DIXIE"..

The same from Rockauto.... TQ...from Autoline....again.... JUNK... the only rebuilt carb that was realy o.k was from Cliff Ruggels ( a Q.Jet ) that carb was perfect.

Greetings Juergen

 

[js29]

me and a friend used a summit carb and intake on a 1974 power wagon one tone minnie pumper fire truck. it had a 2 bbl and was always under powered. it was giving them problems so we installed the kit and what a difference in the way it stated and ran.all we had to do is set the idel . i was so impressed i put a 750 summit carb on my 68 camaro with the same results smooth and crisp response. i would put one on my challenger when the time comes.

 

[Racer57]

me and a friend used a summit carb and intake on a 1974 power wagon one tone minnie pumper fire truck. it had a 2 bbl and was always under powered. it was giving them problems so we installed the kit and what a difference in the way it stated and ran.all we had to do is set the idel . i was so impressed i put a 750 summit carb on my 68 camaro with the same results smooth and crisp response. i would put one on my challenger when the time comes.

Summit sells all kinds of carbs and intakes. What did you use ?

 

[brasil]

@ racer57 you only changed the air door spring ? Interesting... your engine is bigger ( 383 ) than mine (340 )
and my engine seems to "wish " more / richer mixture.... Out of the Box ... the 650AVS runs a Little "flat"...

@ js29 did you use the SUMMIT carb that uses the Holley stuff inside ...and Looks like a copy of the old 4100 autolite ?? This carb has annular Boosters..... These Boosters are awsome !

Greetings Juergen

 

[js29]

Yes !on the minnie pumper we used a 650 vacuum secondary pn mo8600vs. the camaro got a 750 vacuum secondary. thy also make a mechanical secondary version, as i understand a dual plane intake is better for low end, single plane for top end. not shur ware carb spacers help. i know body work better than engine work

 

[brasil]

so perhaps I will think about the summit carb.... semms to have a good Reputation.

Greetings Juergen

 

[js29]

I don't regret the choice. the salesman at summit told me these carb,s were the same as a holley, when i opened the box i said it look,s like an autolite. right after that i was looking at my cousin,s GTX and it had what looked identical to the summit carb he said it was a holley took the aircleener off shur enuff it said holley right on top of it. so the guy at summit was right

 

[brasil]

...found a quadrajet ( originaly those carbs wereinstaled on Dodge Truck with 360 cui engine..

I had best results with this carb on my 75 Pontiac...so I will give "HIM" a try.... will Keep you guys informed

Greetings Juergen

 

[brasil]

..the Q-jet didn´t work... right now I use a 650 EDE.... until my " new " TQ Carb " will arrive the next days...
I found a rebuilt TQon Ebay.. so I bought him.... hope the the carb will work well

Greetings Jurgen

Btw. the 650AVS EDDY works fine ...but a TQ would be the way to go...that´s what I think now..

 

[moparleo]

The AVS and Thermoquad are both excellent carbs. Once set up properly. If you are not familiar with the air valve adjustments etc... on these carbs, get yourself a book or find info online to fine tune your carbs. Good choice. I run the stock Thermoquad on my 72 Challenger 340 and an Edelbrock Thunder Series AVS on my 360 Crate motor in my 73 Challenger. Both run very well, no bogging. Good luck.