[poison heart]

The GMC and pontiac flywheels both have the same size register hole. In the first picture, you're looking at the pressure plate side, notice the small hole for the pilot bearing on the GMC flywheel.

The second picture is the engine side, The crank register holes appear to be different sizes but they are identical. I just used a tape measure so I didn't get an exact measurement but they appeared to be right over 2.5" A 62 crank fit both register holes but the non perfectly circular flywheel flange on the 62 crank would not let me mount the Pontiac flywheel to the crank. Notice how the bolt holes are recessed on the pontiac flywheel but not on the GMC flywheel. I need to compare the early style Pontiac flywheel to the 63 flywheel I have and see what the engine side looks like.

The GMC flywheel in the picture is identical to the one in my star chief. They both used 12" 3 finger style clutches and both have the uneven 6 bolt pattern for the pressure plate.

[Rocky 389]

Originally Posted by poison heart

I see.

There's a local guy right now trying to sell a 57 GMC with a Pontiac motor and a 4 speed. Wants $600 for the motor and tranny. I wish I could pull it off but not for $600


Pretty unique to see a 4 barrel early pontiac especially in a truck.


I don't know where I got this but that's a GMC bellhousing and flywheel. Notice the bellhousing is completely different and has the mounts on the bottom

Must be for a bigger truck...this one is for a 57 GMC pickup with the 347 Pontiac engine. It also has motor mount brackets but they bolt-on.

[poison heart]

Oh wow, I've never seen one like that


The one in front is a 60 bellhousing with a Saginaw and the one behind is my Muncie with the GMC bellhousing. Notice how the GMC bellhousing has more room inside. The 12" pressure plate wouldn't fit in the Pontiac housing.

See how it's fatter at the top compared to the Pontiac one