internal/external balance, 28/50oz ?
i have a 79 f150 302 c6 trans., it needed a new motor so i got a good long block out of a 94. the motor is in and it runs but any rpm above idle it shakes the whole truck. some research has told me the 81+ 302s are extenaly balanced. so i put the 94 harmonic balancer back on, and its still fine at idle but shakes everywhere else.
could it also be the flex plate? could i have it clocked wrong? how do i know where the flex plate weight should be in relation to the crank, i cant find in any of my service manuals anything about it.