Alright guru's, I need some help. I picked up a 67 F100 with "recently rebuilt" motor and c4 trans. Both look like they were cleaned well/painted. Engine runs great, minus a vibe I get Id say around 3500rpm. The vibe happens in neutral and park. Pulled the belt off, ran it...no movement on the balancer, but I figured Id try a second one. Swapped it out and still have the vibe. Im currently not drvg the truck so I dont damage the motor. The vibration is rather significant...

I spun the motor with the inspection plate off and checked to make sure the torque on the flex plate bolts were good, which they were. Whats my next step?

I can pick up a 351w for $900 locally thats been rebuilt...but Id rather save some cash.

Appreciate the advice!

 

After some reading I think I may disco the TC and see what happens.

 

Tranny pulled, going to remove TC and temp install trans so I can start it and see if the TC is my smoking gun.

 

Well, vibe is gone, converter was the problem. Maybe this thread will help someone in the future!

 

Glad to see you found your gremlin. Hope you get to enjoy your truck now.

 

I once spent half a racing season trying to figure out why my engine was missing coming off the line. I would have bet the farm that it was in the fuel system. At the suggestion of another racer I changed the converter. Problem gone. He had had a similar experience.