On a production car it looks to me that the eng/trans is usually higher in the chassis then the rear end so even if they are not offset from side to side they will still have some offset from the vertical. So they will both be on parallel centerlines under load but not the same centerlines. The eng/trans is higher then the rearend on a stock type car as far as I know. That's how they always look to me so the U-joints will still work and lube if the side to side is the same which it looks to be very close in some cars to me like GM and Fords. Most the Mopars look to me to be offset side to side. Ron