Need help with Pantera 2

Need help on a friend's 93 Pantera 2.He Blew his motor up at Gunnersville. He swapped a 175 mariner for a 95 200 mariner with rebuilt powel head with 175. Boat would run 60 GPS with 200, it would run 53.3 with a 23 pitch, tempest plus at 5800 RPM. Then tried a 26 pitch tempest plus at 5500 RPM would run 55. Then we tried my prop off my 93 classic on my boat with a 175 mariner at 5600 RPM, it will run 67 fully loaded. Then we tried it on his boat at 5600 RPM it will only run 60 GPS. Called the mechanic he got his motor from, he says he has had 2 panteras and sixty is all it will run. He called Basscat they said it is a 70 to 72 mph boat with a 200 motor set the prop shaft at 3 and half inches below pad went up and down with no change. Any help will be appreciated.

P2 and 200 engines should run around 70, though on a '93 we don't know condition, weight or another issues. A 175 should punch right at 67, loaded maybe 65-67.

Im running 68gps with my 200. during the summer heat and 73gps in winter. Fully loaded

Boat is fully loaded ready to fish. 60 MPH at 5600 RPM is all it will do. I have a 93 classic with a 175 mine will run 67 fully loaded with same prop.

Has he weighed the boat lately? Is the hull in good shape?

the boat was bought by an older man new and used very little it looks like a new boat have not weighed boat but nothing has been added to boat since the motor was changed the extra 25 hp has made no differance what props should he try

I was just curious if there was water intrusion perhaps. Are those GPS speeds?

gps speeds

Something is definately not right. That should be a 70ish MPH boat with everything perfect. I'd say a different mechanic is in order. If he thinks that's just a 60 MPH boat then he hasn't a clue in my opinion.

I had a 93 with 200. It ran 72 to 73. Something is wrong for sure.