If You go from a run of the mill Magnum lobe to a fairly aggressive Mopar lobe, it could be worth 15-25hp on a 225 easy. But with the long pushrods, and requisite spring loads, stock components are out. Better pushrods are always a good idea on tall-deck Slantys anyways, but may not be in the original budget plan. Springs should always be so, it's a matter of degree & related cost, but expected. I'll try to link My post in Steve's spring shimming thread, about My project.