The Stovebolt Site Forums The Shop Area Engine Shop 292 carb linkage dilemma, remedied

52 GMC 292 engine. I have scoured this forum trying to find a solution to this problem. I am trying to do the linkage on this 292 motor with the new aftermarket carburetor and I am at a loss. Most pictures are for the linkage below the manifold but nothing where it hooks up to the carburetor. It sure would have been easier if the carburetor linkage moved in the same direction as the gas pedal linkage. Anyone have any ideas? I have included a picture of the linkage I have, they have been cut up and welded. Thanks

A 1952 GMC would have probably had a 228 or 248 engine. 292's didn't come out until the mid-1960's or so. The linkage in your picture looks like it's from a 216 or 235 from the mid-1950's. There's not going to be any kind of direct-fit linkage available, so you're probably on your own getting the gas pedal and the carburetor married up. It might be a good idea to look at a 292 in its original application and try to adapt the linkage to the truck you're running. The best approach would probably be to use an aftermarket gas pedal with a cable and fabricate a bellcrank to move the throttle quadrant on the carb, using the pivot hole in the intake manifold as a starting point.
Jerry

Attached is a table of GMC truck engine sizes between 1939-1959.

The photos are of different head ports over those year - in case you are interested.

(thank you, Rob English)

We all know that GMC didn't put a 292 Chevrolet engine (1963 to 1975) in a 1952 GMC truck.
So the question should be, how do I connect my new carburetor up to the 292's linkage and then connect that to my 1952 GMC truck?
First you figure out if the carburetor throttle valve opens when the throttle arm is raised or lowered.
I provided a picture of a 1952 GMC showing carburetor (Zenith carburetor and assorted bell cam and link rods).
Unfortunately from 1963 to 1975 250/292 Chevrolet engines used different linkages. See pictures.
As general rule, if you use the rod from the gas pedal, do not bend it. Long story.
As you can see there are different scenarios. Let us know which direction you want to go.

Yes I guess that would be critical to know which way the throttle linkage goes. If you look at the first picture you see the little ball on the carb linkage it pulls towards the driver Fender away from the manifold

Here is how I solved the linkage when I switched to Carter W-1 carbs. The first photo shows stock linkage, the rope is where the pull cable goes for the transmission kick down cable. The throttle cable goes to the top pivot. The second picture ( green intake ) has dual Rochester Monojets. I used GM parts doubled up with a cross bar pulling both at the same time. Third photo is a close up of the Monojet, the linkage pulls down to open the throttle. The fourth photo has the Carter carburetors mounted on the same green intake, now painted black with adaptors, and the same linkage. Carters pulled up to open the throttles, so a simple flat bar bolted to the throttle shaft makes them pull down to open since it crosses the center line of the throttle shaft. I think I still have some brackets for the cable mount if you need parts.

What is the purpose of the bend in the rod connecting the two linkages? Why not straight?

That's how the length of the linkage gets changed to synchronize the throttle plates on the carbs. More bend shortens the rod.

Kevin is right, it's to hard to get the correct length, so a bend lets you adjust the length.

The other issue is the gas pedal. I don't have a GMC one but the picture is from the 55-59 Chevy FAM.
Obviously this design works with a bell cam/crank mounted on the engine which the 292 does not have.
Many choose to buy a new pedal with a pivot (bell crank) that is made to mount on the firewall.
You decide what you want.

Came across this eBay ad (not mine) which looks like someone else has thought this through and come up with a way to mount that original pivot and rods to the side of the 292 (see pictures in ad).

292 carb linkage bracket

The fabricated plate looks less than refined, but evidently does the job.

The other thing I would mention is that pivot ball shown on the carb will probably need to be removed to allow that hole to be used for the rod from bellcrank up to throttle arm. Also will require some experimentation with bends of the vertical arm so movement of throttle arm is pushing out (towards the fender) from what I can determine from the pictures.

Let us know what you figure out.

That's fairly ingenious. Adapts the 216/235 bellcrank to the block to turn the push of the pedal into a pull at the carb. Pretty pricey for a plate of steel with three holes drilled in it though.

Grab those eBay pics! They will be helpful when you make your own plate!

pauld,

Not sure if this may be of any help, but you might be interested in the "kit" I found and posted in this thread in the Swap Meet.

NOS GMC Accelerator Linkage kit

Good luck on your search for a solution!

Thanks Gdad, if I had an all stock setup, that would be the ticket. I bought a couple of these linkage ends, I think I can make them work. I'll post more pics when I get it done.

Looking forward to seeing what you come up with.

Description and pictures would be most welcome as am sure others may have an interest in your fix for mating up the 292.

Pauld,

What route did you go for a new carb on the 292? I am assuming to went a different route than the old Rochester B? Curious as to what your findings will be on how well it works for you.

HF, I bought a carb off ebay that had good reviews and it was only 85 bucks. When I started the motor for the 1st time it worked great, hope it lasts.
So I ended up using the original gas pedal rod with some extra custom bends in it. Welded a tab to the bellcrank to mount the linkage from the carb. It works pretty good, I can get full throttle with return.

What kind of carburetor is it?

Bet it’s a Daytona.

It's just a Carter knock-off from China. No name on it at all

pauld,

That's a neat solution to the problem.

Thanks for sharing!

Understood. Wasn't sure if you managed to track down a worthwhile suitable replacement/upgrade for the Rochester B. Thanks.