Had this problem on a 351 years back, work was done by a mechanic that was a notch above cro-magnon. He rebuilt the engine, had crank ground and put in new bearings. Not sure if the problem was the main or the rod bearings, but they were way to tight. Truck wouldn't go over 25, after a month we got it up to 40, just before she froze up. :mad: He swore on a stack of bibles that he put in the right bearings and kept telling us the truck would improve once it was broken in.
Have to agree with George, mistakes do happen. Find a set of mikes and snap gauges and double check all of your bearings, something is wrong.
