As far as I know, the rods and pistons are the same. It really doesn't matter, you can get 550hp out of a bone stock 4.6 bottom end with no problems if you tune it correctly. One of the main concerns is the block. The 4.6 blocks that came in the GT's are not that strong, but will handle abuse to some degree. The cobras came with a block that was cast in Teksid, Italy, and then shipped over here. They are about the strongest block ford has ever made. I have about 500hp at the crank. The reason I only make 500 is because of my fuel system. I am running out of fuel at this level. That and the fact that I never really race the car, so I haven't felt like messing with it. If any of you want to read up on this stuff I recommend Sean Hyland's 4.6 Power book. It tells all about the 4.6 motors.dollarbill said:This may be a dumb question but do the dohc cars have better pistons and rods than the sohc. I know the crank is different (I think) but if the pistons and rods are the same then they are not going to hold 550+ horse. Also NoSlow50 are you meaning rwhp or crank hp, its is a big difference. I have heard of sohc with a stock bottom end and good tune running up to 450 rwhp, no more. Most only have 400 for longevity of the stock stuff. For some reason I thought they had a very similar bottom end as the sohc.