1970 Barracuda tunnel with a 1987 merc 1500

[Finch]

Hi all. Just got a ‘70 barracuda with a 1500 merc for my dads retirement gift. He had one as a kid.
Anyway it has a 143/4 x 17 and it’s slow as balls! I want this to fly. Anyone have any experience setting these up? It should be a rocket.
A little more info: 150 impression in all cylinders and it runs great. It’s just super slow.

[Krazymaan]

Are you using any type of jack plate, is the trim/tilt working, how far in the water is the lower unit, I run a 26 pitch prop on my 115 I6. 17 pitch is slow.