If i would have only seen this 2 days ago http://www.mustangandfords.com/techarticles/engine/28898_400_hp_302_small_block/photo_06.html The piston pinholes are offset (note the difference between dimensions A and B). Sherman says installing the piston “backward” with the notch facing toward the rear as shown is worth 15-30 hp, albeit at the price of increased noise when the engine is cold
People have been debating that for the past 40 years. Seems to help on some engines and not make a difference on others. Some say it only helped when running crappy stock heads, kinda like the "long rod" motor debate. The only way to know for sure is to do a before and after test. Most people don't want to bother with that.
