I looked closely at using the top end too but the heads have no water crossover ports, it is done thru an added tube attached to the front of the heads. That would be in the way of mounting a/c, p.s. and alternator. To this point there is no throttle body manifold made for those heads.
The front pully/ balancer is one piece but measures out the same for drive belts.
I was suprised to find the firing order different. this is what makes me wonder about the balance.