Hi Folks. I have a 51 GMC 1/2t pickup with a 216 engine (original I believe). It had sat in the grove for 15 years waiting for a 235 replacement engine. That didn't happen so I decided to use the existing engine. It seemed to run fine (after fuel pump, carburetor rebuild, plugs, points, condenser, etc.). After a few hours of running the clutch finally went. The only real problem I had with that operation was driving the new pilot bearing in place. I had to drive it pretty hard to seat it but no apparent damage. Everything else when pretty smooth. The engine now has a shudder (vibration?, engine miss?) which I really don't know the cause. It happens just above idle then smooths out then comes back at higher rpm. It seems like a miss (listening to the exhaust I can hear it load up and then clear) but it could be some sort of out of balance situation. I just don't know. I had the flywheel resurfaced and replaced the entire clutch pack. Compression is 95, 100, 95, 104, 91, and 120. Vacuum is 19 at idle and steady with appropriate response at accel and decel. The engine hesitates when pressing the accelerator. Any ideas?
