OK..Thanks for the info. This is what happened: Rebuilt C4 and t case in a new(new to me Bronco), while trans was out, installed a new flex plate (for a '77 Bronco). After trans and t case was installed... (not run during this time), installed a new 4 core HE brass radiator. This Bronco has an old A/C and the pulleys are a hodge-poge (mess). The crank pulley is a 3 groove pulley, and the water pump is a single groove. My idea was to install original pulleys; two groove crank pulley and two grove water pump pulley. When pulling the crank pulley off, found it is a 4 bolt pulley (the harmonic balancer looks different from the standard balancer, has a thick part in just one area).
So, I am wondering if the engine is a 50oz balance, and I have installed a 28oz flywheel. The flex plate looked like the one I pulled off, and I have cranked it today; I has a little vibration, but it is running terrible...skipping...running on maybe 6 cylinders. You can idle the engine up to say maybe 1500rpm and it is smooth. It has one little bit of vibration at maybe 2000-2100 rpm, and then smooths out again......Just wondering.
Thanks for the help!!!!!!