Hi Everybody, newbie here. Got a 1956 GMC Pickup with a 316ci engine and manual transmission. Everything is fine with the truck but the clutch is worn out. One shop gave us the 04-002 Clutch kit but it is too small. The measurements of the old clutch kit is pressure plate surface dia : 11.18" the disc is 10.55" and the distance between press plate mounting holes are 12.59" its not quite 11" or 12" but neither it is 10". Local stores such O'reilly and Autozone has Nothing listed for this car. Rockauto listing is same as the 04-002. They do list a 3-arm (or 3 finger) clutch but that is 12" (disc is 11.875") and ours (original in the truck) is a diaphragm press plate and plate dia is only 11.18". I found nothing listed under the Pontiac's and everything I see under the GMC is incorrect for out truck. What could be the solution here ? Thank you
Well, i am the one who supplies the clutch shops We can not find it at our suppliers. This is the issue. The vehicle is in a shop in Europe and I supply the shop with parts. Neither manufacturer that I deal with offers clutch for the 1956 GMC 316ci
Why not have your clutch disc and pressure plate rebuilt. any shop that rebuilds clutches can reface your disc.
Two places seem to get the nod here, Ft Wayne clutch and Kentucky? Clutch. -can’t recall if it’s Kentucky or another name.
I would expect any 11” diaphragm for GM applications will work. There are really only two options, flat finger or bent finger diaphragm springs. The flat finger pp’s use a long throw out bearing and the bent fingers use a shorter t/o bearing.
Tried Kentucky Clutch. They don't even have a listing. I thought it was simple as a SBC but apparently not. the bolt pattern on the block is unique. The 04-002 is a multi GM Clutch. It was used for decades. Its close but the bolt pattern of the press plate is different.
AMS AUTOMOTIVE / RHINOPAC 04002 Specifications Clutch Disc Diameter 10.375 IN. Clutch Slave Cylinder Included No Disc Material Organic Flywheel Included No Input Shaft Diameter 1.125 IN. Input Spline Quan***y 10 Pressure Plate Bolts Included No Pressure Plate Type Diaphragm style This is that is NOT good. Too small.
I’m not sure what you meant about “….the bolt pattern on the block is unique.”, but look into any 11” diaphragm clutch for a GM car with a 1 1/8”, 10 spline disc. That will fit your needs.
sorry, had a lot of things in life that needed tending. SO what I meant is the bolt pattern is different on the block. It is not a SBC nor it is an engine that was used in a lot of cars/trucks. It was used for 3 years in a Pontiacs and 2 years in a GMC pickup. No, the SBC Chevy engine bolt pattern is not the same, it won't fit. The old clutch is not an 11" clutch. Its 10.5" so its neither 10 nor 11. The 10" was too small but the 11 is too big. Even though the 10" we bought was not 10" either, it was 10.375 so that was already a sizeable margin error. But that is still small, the holes are not lining up. I listed the exact dimensions of the original clutch disc/pressure plate. The spline and the shaft dia is correct, no issue with that. Its almost spring and we still can not put the truck together because of this issue. I see no listing anywhere for a 10.5" clutch but the truck came with that.
At this point, redrilling the flywheel would be the next step. That way you could use a common clutch setup instead of trying to get unobtanium.
I found a listing for a replacement clutch on partsgeek.com, although I can't vouch for if it's correct or not: https://www.partsgeek.com/kzq9sf6-g...3Bu-uvrFsnzPddlLMCpAZvhN0l37jtrgosE_96VoEdfNw It does list some dimensions, it's 10.4" diameter.
From 1955 to 1959 when a GMC pickup was ordered with a V8 the engine used was the Pontiac and yes, I did understand that the bell housing bolt pattern was for a Pontiac block. Pontiac used that bolt pattern from 1955 through 1963. I just measured an aftermarket SBC flywheel, it has multiple bolt patterns for different sized Borg & Beck three finger and diaphragm pressure plates and also the Ford Long style pressure plates. One set of holes for a B&B clutch measured 12 5/8”, that will be for an 11” pressure plate, the other set is 11 5/8” for a 10 or 10 1/2” PP. If you can visit the auto parts store and measure an 11” pressure plate two bolt holes will be 12 5/8” apart, that will fit your flywheel per the measurement you mentioned in your initial post. Regardless of what came out of the truck when you took it apart doesn’t matter now. You need a pressure plate to fit your flywheel. Also, if you can go to an independent parts store, rather than one of the chain stores, the counter man will likely be more tuned in to what you need. Update- I had forgotten you are in Europe and stores most likely do not stock American auto parts.
Something that I've done in the past when I installed a new clutch is to write on it with a marker where I bought it, the part number, and the date I installed it. If you have the flywheel redrilled to take a more common clutch, specify that information as well.
Pretty much what Fordors says, You have Pontiac parts 347 & 336 parts should do the trick. But not 370 parts as that was an Oldsmobile 371 engine in heavy trucks, not the Pontiac 370. Good source- https://pontiacsafari.com/
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