67 Cuda: disappointing dyno numbers, need some advice!

I am a firm believer in if it is not broke dont fix it.
Without tearing the whole top end off the engine, and measuring everything, there is no way to tell if your new rocker arms will clear the pistons.
It would really suck, to jam a valve down into a piston, even though I dont think you would, but I am not a gambling man, so I have to know, I do know that the factory rocker arms are all over the place, so you may be changing the valve train clearance more than you think.