One shop here on the west coast did a comparison on the dyno with before and after on a stock 496HO, understand they saw about 25HP gain which is about what I would expect to see from an e-top type header on a 496.
It will be interesting to get Bob's dyno numbers, his dyno's are really real world and I expect about the same result, time will tell.

Best Regards,
Ray @ Raylar

Bob, did you ever test the ETop?

I haven't done the etops on a 496 yet. I have actually tested a set on a 502. Not sure why but he bought the 496 etops and converted them for the 502. I didn't get to do a before and after but they looked and sounded good. They had changed the cam to one that was way too big for the applictaion and I was concerned about reversion. But, there didn't appear to be any so that's encouraging. It showed a 60 hp gain at the prop, but that was increased compression, cam change and reprogram on the ecu. That's all I know right now.

UOTE=Keith Atlanta;2908523]Bob, did you ever test the ETop?[/QUOTE]

heres one few people even consider when talking about speed in their chosen ride.........
i noticed that some of the folks that posted are doing most of their boating on rivers...... rivers have flow ,current..... usually to the tune of 2/3 mph i know my local one does........ to get true speed you need to subtract water speed