Yep , thats the post everyone should read and pay careful attention to.

As for the interior pipe size, length and design, if you are to beleive they are constructed per the cutaway on the 496 set, then I would have to opinion that they will prbably not make any more power than the stock 496 Mercury manifolds. all that extra water around the pipes is another question as to what happens when water flows and pressures from a used water pump starts dropping slowly with hours and use??
Just thinking inside the box here.

Best Regards,
Ray @ Raylar