Harmonic balancer

[Jeff Chambers]

If they mean what I'd think they mean, then its what you would want. The late model 5.0 has a 50 in-oz external balance; early model 5.0 & 351 a 28 in-oz external balance and the late model 4.6/5.4 an internal nuetral balance. To internally (neutral) balance your 5.0 requires the machine shop to do a dynamic balance of the rotating assembly, usually done by adding heavy metal to the crank. You want the external balance. Stock or aftermarket is up to you, but you get what you pay for. I've got a Romac balancer on my engine. Kinda pricey (~$300), but good insurance given what I've got in the rest of the motor.