I just bought the 38 coyote beep beep.
It has twin 496's with trs drives.
The boat is running 5000 rpms and only doing 55
What would the best props be for top end?

need more information.your current props your running and pitch and diameter..the revolution 4 props work well on the older non stepp hulls..

Which 496's? If they are the 375HP, with TRS on a 38 foot boat, sounds about right.

They are 2001 8.1ho 496's 420hp

At 420 a side I would be hoping for more also, what props are currently on there? Is this the boat from lake Worth FL?

In 2001 the engines would be 425HP with a operating range of 4600-5000.
Still need to know the propeller model and pitch to determine how efficient you are running.
More than likely a 3 blade propeller will give you the best speed but not necessarily the best over all performance.

Brett