i have a big block in my shop came to me blown up the roller lifter were blown up cam trash it had a gear drive and the lifters that were the next to the gear drive were junk it will not have a gear drive in it when it leaves my shop the guy was thinking i was joking i told him NO way would he get that gear drive in that engine from me . they add hamonic so if it made 10 hp on the dyno i would not use one why? they break parts by adding hamonics i build stuff to say to gether i do not need a dyno for that