RBake

Ok, I finally got the whole tach issue fixed. I ended up with 4600 rpm WOT fully trimmed with a 4 blade 22 pitch mercruiser prop. But I'm only getting 52 mph top speed on gps with 3/4 tank of gas and me, my wife, and 8 month old. What's up with that??
My engine is a Marine Power replacement 454 Carb'd that says it puts out 380 HP. That's more than the stock Mercruiser 454 that came in the boat.
I'm thinking about a 23 pitch 3 blade Mirage. But will the extra pitch lower my WOT Rpm's?? Is it possible to get to 60 MPH with just changing the prop??
It gets out of the hole fine right now.

Oh yeah, My graphics came in today. I'll try to get some pics with them on this weekend.

29scarab

Say bro,

Your not going to make 60 with just changing the prop if your only running 52.

I was a running a stock 23 pitch in my 502mpi before I put the HP engine in it. And that was at taching 5000 with it. I was only running in the upper 50's low 60's with that set-up.

Your going to have to put some HP in it when you get some money to do so. ITs a heavy boat and needs Horse power. I'm pumping out about 660 HP in mine right now.

Its a 502mpi with zero gap rings, Crane HP gold roller rockers and a Whipple super charger, Stainless marine exhaust. I'm running low 70's now.

I know your not happy with the speed, but you have a good start with the Scarab. Its a great hull. The 454 is a good engine. There's a lot you can do with it.

If I can help with anything give me a shout!

Good luck!

Shawn

Hot Boat

The never ending quest for more speed.

be careful it is like a disease. even if your boat ran 110 mph you will want it to go faster.

The rule of thumb is $1000 for 1 MPH.

Its all a mater of how much you want to spend.