Rocker covers give them up straight away!
I'm sure there was a slight height difference when I put the VP engine in my Overlander (with a Redline manifold and carb) but I can't remember where it was. Are the pushrods the same length as a carbied 253/308? Not a combination i'd recommend on a everyday driver, lost heaps of low rpm torque compared to the red 308 using the same carb and exhaust. HEAPS louder though.