So, I have a super low milage 400 that I acquired. And I decided to take a bunch of extra parts I have and put a Dyers 671 Blower on it.. Yes useing stock pistons, rods and cast crank.. I know there's so many red flags already. But this is LOW budget and really if/when it grenades I'll gaurentee I'll be cheesing ear to ear.. The 671 will be heavily underdriven and wickidly low boost approx 4-5 lbs. And I'll keep the timing retarded so it Might (?) Last ha-ha.. Anyway my main question is the 400 is externally Balanced, and I have a hub for an internally balanced 440, so I assume it'll viberate quite badly.. So next option anyone have a recommendation for a 400 externally balanced harmonic Balancer.. That'll hold up to a 3" Blower belt. Or any input on it? I know it should be dual keyed but... I'll chance it. (2 friends of mine both run blowers..Street use.. With one key and hasn't failed them yet) again this is a fun low budget, bunch of crap I have laying around, Street Engine that will see 5000 rpm max.