I'm building up a Buick straight eight presently. After careful measurement the best ratio possible from the stock rocker is 1.51:1 when the adjuster ball is screwed nearly all the way up into the rocker. This is unuseable as the oiler holes no longer line up in this rather tenuous oiling setup to begin with. With the adjuster lowered to a more practical place in the rocker the ratio drops to 1.42:1.
My solution was to physically relocate the rocker arm shaft .062 closer to the pushrods. I offset bored and rebushed the rocker arms and shaft stantions .062 towards the pushrod side of the engine.The net result is I now have a 1.66:1 rocker ratio, and no interference at the pushrod holes in the head.
It cost me a week of spare time making the jigs to bore the rockers and stantions another week to do the machine work and about $80 worth of bushings and high temp bushing lock.