There is nothing to feel for on the balancer. Some people enjoy seeing their name in print and will write anything, with no regard as to whether it misleads anyone or not. As I explained above, you have correctly determined that you have an unbalanced damper for an externally balanced sbc engine.


The fact that the flex plate hits on the dust shield, suggests that the flex plate has 168 teeth. The Corvette flex plate had 153 and was smaller in diameter. The only externally balanced two piece seal flex plates Chevy used were for the 400 SBC and the 454 big block. The unbalanced flywheels or flex plates were available in the larger, 168 tooth configuration, only. Take a look at your starter. The 153 tooth 'plate uses a starter with a straight across (perpendicular to the crank centerline) bolt pattern. The starter used with the 168 tooth 'plate uses the two holes that are offset from one another. Of course that only applies if you are using the large, stock, early Chevy starter.


The converter is meant to bolt to the flex plate with three bolts. As with ring gear tooth counts there are both large and small converter bolt patterns. If both your flex plate and torque converter are set up to accept both, they can be attached to one another with all 6 fasteners, three in each bolt pattern.


I mentioned that in my first response, even though one that wouldn't read your post, faulted me for making an idle speculation.


It is almost impossible to guess at what an unknown engine wants for tune up specs. It is difficult to believe that the ECM timing curve would be too aggressive. Ideally, you shouldn't hear it knock. The EST should pull the timing back before the knock becomes audible.

The vibrations are anybody's guess. Possibly the unbalanced parts don't belong on that engine. Maybe it was hastily assembled and not properly balanced. The vibrations could only be caused by a bad tune. There is no way to know by long distance.

RACE ON!!!

 

There is nothing to feel for on the balancer. Some people enjoy seeing their name in print and will write anything, with no regard as to whether it misleads anyone or not. As I explained above, you have correctly determined that you have an unbalanced damper for an externally balanced SBC engine.


The fact that the flex plate hits on the dust shield, suggests that the flex plate has 168 teeth. The Corvette flex plate had 153 and was smaller in diameter. The only externally balanced two piece seal flex plates Chevy used were for the 400 SBC and the 454 big block. The unbalanced flywheels or flex plates were available in the larger, 168 tooth configuration, only. Take a look at your starter. The 153 tooth 'plate uses a starter with a straight across (perpendicular to the crank centerline) bolt pattern. The starter used with the 168 tooth 'plate uses the two holes that are offset from one another. Of course that only applies if you are using the large, stock, early Chevy starter.


The converter is meant to bolt to the flex plate with three bolts. As with ring gear tooth counts there are both large and small converter bolt patterns. If both your flex plate and torque converter are set up to accept both, they can be attached to one another with all 6 fasteners, three in each bolt pattern.


I mentioned that in my first response, even though one that wouldn't read your post, faulted me for making an idle speculation.


It is almost impossible to guess at what an unknown engine wants for tune up specs. It is difficult to believe that the ECM timing curve would be too aggressive. Ideally, you shouldn't hear it knock. The EST should pull the timing back before the knock becomes audible.

The vibrations are any body's guess. Possibly the unbalanced parts don't belong on that engine. Maybe it was hastily assembled and not properly balanced. The vibrations could be the result of just a bad tune. There is no way to know by long distance.

RACE ON!!!