motor plate phasing?!?!?!?!?

I think the engines are offset side to side in the front towards the passenger side. Look under the hood of a B body, the engine is offset from the factory. (offset from center)
Of course if you can run it totally centered by whatever means,even more the better.
From the factory, this had to do with interference of componnents , mostly steering.
The ideal setting is totaly centered, level side to side and level with rocker panel from front to rear. However, it can be nosed up in the front a bit from level and offset to the passenger side. Never nosed down in the front. dont know how they did the original big block A bodies.