2GV to AFB

[54blackhornet]

Looking for some help on carb swap. I have a 2GV on a 307. Can’t seem to get it to work properly, fast idle and divorced choke issues. I have a Carter AFB sitting on the shelf that I removed from a 350 that was running fine with it. Was thinking of trying it on a factory cast iron GM spread bore intake with adapter. Thoughts ?

[Warrens69GMC]

do you already have the cast iron intake?

[54blackhornet]

Yes I removed it from a 71 350. Problem is it has no shield underneath the cross over.

[Ziegelsteinfaust]

Adapters in my option with the factory q-jet intake well. They way the holes are set up leads to a primary imbalance for lack of a better term. Which restricts the even flow of the primary.

If you have or purchase a low rise dual plane like edelbrocks performer.

Then a adapter works well if needed, but usually not needed.

I would prefer a q-jet but it's up to you.

[54blackhornet]

The AFB is model # 9635S, anyone have experience with it ? Will the 2GV linkage line up ? Intake has the threaded hole for original coil mounting that the linkage mounted to originally.

[Warrens69GMC]

I personally would run 2701 Edelbrock .

https://www.amazon.com/Edelbrock-270.../dp/B00063046Q

no name, is cheaper
https://www.ebay.com/itm/26553408677...Bk9SR4al0MCVYg


The 9635s is comparable to the 1406 Edelbrock.

[Ironhorse]

Originally Posted by 54blackhornet

The AFB is model # 9635S, anyone have experience with it ? Will the 2GV linkage line up ? Intake has the threaded hole for original coil mounting that the linkage mounted to originally.

I have that same carb on my 71 long bed 4x4. Google says the #9635S AFB is 625 CFM over the #1406 which is a 600 CFM carb. Pretty much a stock 350 with a Edelbrock Performer intake. 350TH auto and am very satisfied with how the truck runs. Stock cast iron straight down 4x4 exhaust manifolds. Not sure about the 2GV linkage lineup as my truck being a 71 4x4 used a cable linkage which we had to modify for the AFB.

[54blackhornet]

I do have the stock cable linkage you mention, it’s a 71 C/20. Can you please tell me a bit about what you had to modify to make it work properly ? Thanks

[Ironhorse]

At the time of the carb, engine and transmission swap I was working a LOT of overtime and only got to do a bit of the engine bay cleanup and lighter stuff. Mechanic friend of mine running a shop did the actual change over. If you have a cell phone PM me your number and I will send/text you some pics of the cable attachment to the carb. Looked to be pretty straight forward and simple.

['68OrangeSunshine]

Originally Posted by 54blackhornet

The AFB is model # 9635S, anyone have experience with it ? Will the 2GV linkage line up ? Intake has the threaded hole for original coil mounting that the linkage mounted to originally.

Yes. I have a 9635S Carter AFB Performance Series. I run it on my 350 cratemotor in a '71 GMC Jimmy.
The 9635S is mounted on an Offy Squarebore/Spreadbore adapter over a Weiand aluminum intake. [Have to dig to get P/N.] I have a 1'' phenolic spacer above the adapter and under the carb to combat vapor lock. [I live in Southern AZ.]

The 9635S is roughly equivalent to the Edelbrock 1405. Mine is a manual choke. 1406 is the electric choke. They are rated at a nominal 600 CFM.

[If Carter rated the 9635S at 625 or 650 CFM, it's more of a difference of design philosophy than real world CFMs.] I use the Edelbrock Carb Owners Manual for tuning. If you talk with the Edelbrock Tech Line guys, don't say it's a Carter, they will clam up. It's called a ''Performer'' now, not an ''AFB.''

These carburators were all made by Weber in the same plant. Eddies got a shiny polish and a red decal. ''Carters'' got a snazzy _PERFORMANCE SERIES_ tin marquee to mount on the front. Took mine off when I saw the black paint wasn't spray Carb Cleaner-proof. Federal Mogul, who had bought the Carter name, lost interest in the high performance aftermarket in the 2000s and quit selling them. Edelbrock now is the exclusive AFB-type carb seller.

The 9635S at 600 CFM may be a bit large for a 307. You might be better with a 1404 at 500 CFM. That's what I run on a 292 L6, bored .030-over [=296CI]. Edl-1043 is the electric choke 500 CFM four barrel.
[I prefer a manual choke.]

However the Aluminum Four Barrel [AFB] design runs the secondaries as a demand type operation, so you can't pump more A/F mixture than you can use.

As far as linkage, IDK. On the '71 350 V8 I had no problem with the stock accelerator cable. On my '68 C/10's 292, I replaced the gas pedal/push-pull rod carb linkage with a cable system. Because the carb runs ''sidesaddle'' on an L6, too many bellcranks, levers and widgets were in the linkage, and it was failure prone.

[Ironangel]

Originally Posted by 54blackhornet

I do have the stock cable linkage you mention, it’s a 71 C/20. Can you please tell me a bit about what you had to modify to make it work properly ? Thanks

The factory spreadbore intake will accept the brackets for cable accelerators as well as the kickdown cable for 350THM's. A Quadrajet will beat the 2G carb and the AFB carb for MPG's. You have an intake with tiny primaries, make the most of them with a 4MV Quadrajet. The vacuum operated secondaries will only allow enough air the motor wants so a properly set up 750 cfm Q-jet will suit that 307 perfectly. Leave the AFB on the shelf...IMO

[geezer#99]

I agree!
Leave the afb on the shelf. Along with the intake, the adaptor, the throttle linkage and all the rest of the stuff.

Fix the two minor problems on your 2gv.

[54blackhornet]

Thanks everyone for your advice ! After reading the comments I believe I will continue to figure out the 2GV. I only use the pickup for firewood retrieval on my property. I appreciate everyone’s suggestions…Jack