Thanks for the info on the rockers. I was able to check in some parts books, and found out that the GMC and 235 Chevy use the same front cover gasket and front main seal. So, the outside diameter of the harmonic balancer, (where the seal rides), must be the same. Don't know yet if the crankshaft snouts are the same, and how the pulley spacing would match up.
Did you ever figure out how to get the pressure plate off? I have a small block flywheel on my 302 and have to depress it to get it in and out when working on the clutch. I use three nuts between the arms and the plate housing to keep it depressed, then remove them when work is done. I have some wire connected to them when they drop I can pull the nuts out. Sorta hokie but gets the job done. Works great too. I had the flywheel machined at a local shop and pinned/indexed to the crank when when I had it all balanced. An old timer gave me the tip on the small block flywheel. He said they used to do it all the time back in the day! I figure why not give it a go and see!! Oh and I use a old car starter with the later flywheel, with a 1/2 ton bell housing.
The dampers on the 270 and 302 interchange, but the 235 damper won't work on the GMC. The GMC dampers bolt onto the crank, but the 235/261 dampers press on.
The Jalopy Journal
