351 (both W & C) are also 28.2 oz/in. HiPo is the same imbalance but uses a bob-weight to counter the extra weight of the 3/8 rod bolts and C2 caps along with a balancer with more mass. Some claim the HiPo imbalance as being 30.4 oz/in but I believe they aren't compensating for the offset of the bob-weight from the balancer.Ah, must be the 351 I'm confused with? And the hi-po different too, correct?
The '82+ 5.0HO, however, has a 50 oz/in imbalance to accommodate the revised "HO" firing order using the same crank as the "non-HO".