351w Balance issue

[skooli]

Does anyone know anything about late model 351w truck engines? I just put a '94 351w in my 68 fastback and it's extremely out of balance. I have a 50z harmonic balancer with a matching flywheel, but I was told by someone recently that late model 351 windsors are internally balanced. Is this correct? If so how do I go about fixing this issue?

[dutch]

Your 351W engine is 28oz external balance. A good machine shop can rebalance your 50oz pieces to 28 if they have 28oz pieces to match. If your 68 had a 302, those pieces will match the 351 too, as they would have been 28oz external balance.