RazorsEdge

If you happen to come up with the specs, I would love to see them.
Thanks,

cuposterchild

I will see what I can dig up...I can post the dyno numbers before and after no problem, the parts list was all handwritten so I will see what I can make of it tonight.

Pat McPherson

From what I remember about the upgrades Gary did to that engine are the following:

The heads were milled to increase the compression and race ported for better flow.
An Inski roller cam with all the mating valve-train components installed.
The intake was replaced with an Edelbrock Vector single plane and on top is a 850 Demon carb.
Imco Power flow exhaust replaced the cast iron crap.
Last, I believe is an MSD ignition so she will rev higher than the stock Merc 5150rpm.
I would guess, between 5 & 6K worth of upgrades...

cuposterchild

See Razor what did I tell you But I think it may have a Demon 825 carb....will double check though. The rest is right on. The motor is a nice piece, and really came alive with the work Gary had done. Revs a LOT higher than a stock 454 that is for sure. As if this motor wasn't enough in its N/A form, there were plans for a blower (177 i think) but hatch clearence became an issue. Shop up outside of Albany did the work.

Stormrider

Razor, Jeff's been on this thread and would be happy to talk to you. For less than 5-6 you can get your engine rebuilt w/o having to touch it... +exhaust.

New better heads will make a big difference in power too.
I paid around $1000 for dart iron eagles.

Best of luck to you, and keep us updated.

RazorsEdge

Always,
After a lot of personal debate, I ordered my steering (Zeiger Single Ram, Full Hydraulic) and indicators (Livorsi) from Trick Marine today. Hopefully they will not take to long to come in.

I am currently pushing a 24" Bravo1 prop to 4900 RPM for 66mph (GPS) in a light chop (1 to 2 ft), 3/4 tank of gas and 2 - 200lb adults. Do these numbers seem par for the course? I have to trim the Bravo1 pretty far out as the speed increases, but the ride is outstanding. The whole boat feels like it is lifting higher out of the water. Cruising back in late Sunday, she road like a champ in 3 to 5 foot rollers at around 50mph. Zero tendency to drop her nose, and running real strong.

I will probably have Mark from Litre Marine (local) do the engine after this boating season. He thinks I should go with displacement, but I am still on the fence. If I can squeeze out 500HP and good torque numbers out of my current block and crank, I will probably keep my 454 Mag (cheaper). I know I will have to drop some $$$ into the drive so she can handle the extra power with reliability, so I may run into a money issue later down the line.

Do you think 500hp will be enough power to turn a 26" Bravo 1 to 5500 to 5700 RPM? With the same slip #'s that should put me between 80 and 84mph.

What would by cruising RPM be with a setup like this? Cruise speed between 65 and 70mph would be ideal.

What about for P6 (OPA) Race Class combo?
22" at 5600, 24" at 5250 or 26" at 4800

Is their anything else I should be thinking about?
I really love hearing all of your thoughts.

Pat McPherson

Bravo 1 props do give great overall performance on these hulls. If you have a B1 altered to give more bow lift then you will not have to trim out/up as far and top speed will increase.

Your speed does seem to be a click or three slow. The guys I have talk with have run 25p Mirage or 26p Bravos on 24 Supers or Panteras powered by 454Mags. Running light your boat should run in the low 70s.

When I first bought my boat, I installed a 310HP/7.4MPI. With two people and 1/2 tank the boat would run 65mph with a 25p Mirage+ and 63mph with a 24p or 26p Bravo 1. I had my 26p B1 labbed a couple of times (long story) and got to the same top speed as the 3 blade. The fastest I got the boat to go with the 7.4 was about 68mph running real light.
Last year I installed a 415HP/502MagMPI and with a 28p Bravo 1 she ran 74-75mph consistently. This year with a modified B1 she is a bit faster.

With a 500HP engine a 24' Superboat should run over 80mph.

As for propping a boat for racing, that will depend upon your engines torque curve. If you build a 500HP/454cube then prop for 5500-5600, if a 500HP/502 then 5200-5300. My bet is that a lager displacement engine that creates its max torque at lower rpm can spin a bigger prop and will accelerate the boat faster in turns and be better for racing.

RazorsEdge

Did my slip number look correct?
I am currently pushing a 24" Bravo1 prop to 4900 RPM for 66mph (GPS) in a light chop (1 to 2 ft), 3/4 tank of gas and 2 - 200lb adults.

What RPM Should I be able to turn a 26" Bravo1. My engine was rated at 350hp at the prop and I have a Stainless Marine Exhaust on that. So lets say 365 at the prop (this may even be generous).

Pat McPherson

The slip % looks about right.
I would think you should be able to spin a 26p B1 at 4800+rpm.