The Stovebolt Site Forums The Shop Area Engine Shop Accelerator to Carb Linkage

Back when I freeze-cracked the block on my 235, I replaced it with a 235 block out of a '61 Chev Biscayne. I've now noticed that the mounting location on the block for the accelerator to carb linkage is in a different location on the car block than it was on the old truck block. Rather than try to cut and shorten the linkage rods and risk cutting them too short, does anyone know if the mounting location on later model 235 truck engines would have been different than on a '55 235 truck block? I'm thinking if the later 235 car and truck engines had the mounting connection in the same place, I can probably order the linkage for a later model 235 truck engine and have it all hook up fine without modifications. I could probably try to find a car linkage set, but I don't know if they would have come through the firewall and hooked to the accelerator pedal the same as they would have on a truck. The mounting location on the old 235 block was right under the center port on the manifold. On the '61 235 car block, the mounting location is toward the firewall and next to the soft plug. It is about 3" estimated closer to the firewall than it was on the truck engine.

Is there a hole in the new block at the location of the pivot pin in the old block?

I ran into a similar problem with my truck. When I bought my truck, the previous owner had hired somebody to remove the engine so it could be rebuilt, and hired a different person to reinstall it. Somehow during the process,things were lost,among them the throttle linkage.
I bought a throttle linkage assembly complete from a wrecking yard which included the "through-the-cab" part.It supposdly was for the same year and looked correct but would not work.
My mounting pin was on the block to the rear of the manifold. I solved the problem by buying threaded rod and threaded ball-socket ends at the parts store. I cut the threaded rod as necassary,screwed on the ball-socket ends to make up the rods which were adjustable to some degree. The only part of the original assembly from the wrecking yard was the v-shaped bracket which mounts on the pin screwed into the block.It works well in one sense,but I still have not yet contrived a satisfactory return spring hookup.
meansam

i cut mine , threaded the ends - used lock tight with 2 jamb nuts on a " coupling nut " ( that is a drilled & tapped nut , where you can insert from each side ) .

Are you certain that the boss isn't there for the truck linkage? I was always under the impression the both bosses are on the block, and just the one that is used for original application was drilled.

Nope, no hole at the location of the pivot pin that was on the old block. I double-checked that. The original block had a raised area (boss I presume?) at the location of the pivot pin and a raised area that was also threaded where the pivot pin on the new block is located. The new block has nothing where the pivot pin was located on the old block. If I knew how to attach photos, I'd show you what I mean.

1960-62 235s do not have the front throttle pivot hole.
On the conversions I do, I drill the side of the block and install a pipe plug that I have drilled and taped to except the pivit post.
You can see the finished set-up here. http://picasaweb.google.com/pre68bowtie/MechanicalPart/photo#5031057369668349522

The pivot is: 12 9/16” from rear of block.
4.850” from deck of block.

PRE68DAVE IS A GENIUS..............

Dave, that is exactly what I'd like to do. Would you by any chance have the location measured so it would come out where it is supposed to be? I don't have my old block anymore, so I can't get the measurements. Also, I would assume you are drilling into a water jacket on the block. What did you do to prevent leaks? This looks like a great idea, but I want to make sure I do it right. Thanks.

I went back and read your post, Dave, and had missed your measurements the first time. Sorry about that. The only question now has to do with drilling into the water jacket and leaks.

I use Loctite on the threads.

I'm wondering how difficult it would be to fabricate the linkage that could operate from the pivot point that is already there. It would mean shortening the accelerator rod and running a rod up to the carb that would be drastically different than what I have. Has anyone tried that modification? Dave, your information is great, but the engine is already dropped in the truck and it would mean taking off the manifold, carb, etc, to be able to get down to where I would need to measure and drill the block. It would mean cutting the accelerator rod and that one makes me nervous. I'd want to make sure I cut it right the first time because there would be no second chance.

Rick,
I did exactly what you say for the '62 261 in my truck. I took the accelerator rod, shortened it, and re-bent it to match up with the new linkage. I made a new pushrod up to the carb because mine was all wrong. Then I noticed that the accelerator rod binded a bit in its travel so I used a vise to take some of the curve out of it. It works great, now.

It took me two tries to work out the rod to the carb but the one from the accelerator pedal was pretty easy. I did the carb to bellcrank rod first to establish the end points of the throttle travel. Then I wired the throttle open all the way and shortened the pedal pushrod so the pedal almost hits the foor with it wide open. It worked out just fine.

If you screw up on the pedal push rod you (or someone else) can weld a new piece on it, but if you do the carb piece first you should be able to get it right the first time. The hardest part is making it clear the exhaust manifold and the oil lines on the 261.

Thanks Rick and 4onthefloor. I'm putting together a 53 with a 62 261 but have not gotten to the accelerator linkage yet. I'm sure your experience will save me a headache or two not to mention time.
Jerry

Has anyone considered changing to a throttle cable, vice the linkage?

I'll try posting a couple of photos here. By way of an update, I ended up doing what Four on the Floor recommended. I built new linkage from the pivot point up to the carb and cut the linkage from the pivot point to the accelerator pedal. I ended up fabricating a clip at the oil pan to hook the return spring to and then I drilled the linkage from the pivot point to the carb to attach the other end of the return spring to. I had to straighten a few spots on the accelerator rod in my vice, but all is working as it should with no binds. [img]http://i152.photobucket.com/albums/s161/Rick_53/IMG_2406.jpg[/img] [img]http://i152.photobucket.com/albums/s161/Rick_53/IMG_2406.jpg[/img]

Well, I sisn't mean to add the photo twice, but I guess I'll eventually get the hang of it. Anyway, you can see from the photo how it went together. I think I did it right this time. http://i152.photobucket.com/albums/s161/Rick_53/IMG_2407.jpg