Increase top speed of MERCRUISER 5.0?

[justjoshin]

I have a 2002 19' VIP Vindicator with a 19 pitch prop that does about 56 MPH and everything is stock on the boat. What I need to know is how I can increase the top speed before I go out and waste a ton of money on useless junk. Any info. would be helpful.

[Canada Jeff]

Depends on how much you want to spend. Supercharging would be my first sudjestion.

[justjoshin]

I thought about a supercharger, but I was trying to find a way to increase it without going that way. I was hoping to find a cheaper way to get maybe 8 to 10 mph out of it.

[gnarley]

What is the HP rating & CID, how many RPM's are you turning at 56 MPH and what is your gear ratio?

[justjoshin]

It has 220 HP and the CID is 305. It is running 4700 RPM @ 56 MPH and the gear ratio is 1.62-1.81

[dawgdude]

I got your post about needing cheap speed. Just talked to a guy that had his bigblock Vindicator pcm reprogramed. Said that it made a large difference, like 4 to 5 mph. Don't know how accurate that is though. He said the reason he had his done was due to it being way to rich. Turned his transom black. He said that the speed was a bonus. I'm going to look into it,, that is if I can find someone hear local to do it.

[justjoshin]

Thanks, I will keep checking to see what you find out about it.

[SUPERCREWJOHN]

I would trade your 5.0 for a 350 or a 6.2. That will get you the stronger internals that you need for more performance.
If you must hold onto the 5.0 someone probably makes a Cam and a trottle body and some computer tweaks ( like Arizona Speed and Marine) to give it a bit more juice.

[77charger]

Havent seen anyone say how much your hp your drive can take.You wouldnt want to go past its rating or it could get costly.assuming it has the alpha?

[Strictly Verboten]

The 220 HP 5.0 has a 2bbl carb and no computer, just a thunderbolt V ignition. Stock heads are chevy vortec. Cam is hydraulic/roller. Replacement cams, intake and carbs are available. Generally mated with an Alpha drive, 300 hp max.

[justjoshin]

Does anyone know an online store that I can find replacement cams, intake and carbs?

[justjoshin]

I am looking into a marine 4 bbl carb. for this 305 engine and I just can't find it. Can anyone help me out (part number or site to check out). Thanks.

[Super D]

What diameter is the prop? 14? I just got one (14x19) for my 4.3 and am wondering how it will do. I would try the pcm as a simple, affordable upgrade before getting new hardware. You could also experiment with another prop. Good Luck.

[Nokomis]

Justjoshin, I don't know if the alpha will stand up long term to the power you need to put in front of it to get another 8-10 mph. Why not sell it, add the money you were gonna spend on upgrades, and buy a used boat that will do what you want? Just my two cents.

[justjoshin]

I am planning to try out some different size props this week before I do anything. Have a 21 & 23 pitch to try out and see how it works with those. As far as selling my boat, well I love this boat and wouldn't think of doing that. I just was sondering if I could maybe get a little more out of it. If not, then there is no problem with that. But I do thank all of you for your information.

[Nokomis]

Thats cool that your that happy with your boat. I had a 20ft Baja that I went the upgrade route with and when it was all said and done I probably should have left it alone.
Good Luck

[tahoewakeboarder]

I have yet to find a supercharger for the 5.0 Mercruiser. I'm not sure about the internals on the engine...but it's a given an upgrade to a Bravo would be necessary if a blower was used.
Hindsight is 20 - 20 of course...should have bought a boat with the 6.2. Kinda hard to pull out a 2001 sterndrive with 175 hours though and throw 13 - 14 grand on new power.

[Hallett19]

The last thing you want to do is over-carb that motor. I have a 460 BBF in my boat and a 750 4 bbl is considered over-carbing. I would try to put some new exhaust on it assuming you have through prop exhaust. The only thing you can do short of tearing the motor down is carb, headers, nitrous/blower or re-prop it, just be carefull with that alpha, they cant handle much power at all.

[502procharger]

i guess i will be the asshole. you will not get 10mph out of any upgrades to that motor to matter what you do short of supercharging. End of story. the alpha will blow apart first time out if you could find a supercharger anyways. i just want to tell you the truth. be happy with the boat and enjoy it. if you try to get that kind of performance increase out of it you will be dicking around with it more than having fun with it. when you buy your next boat go BB.

[Dennis Moore]

56 mph is really good for that boat! Adding a four barrel would be a nice addition, go with an Edelbrock set up. Performer square bore carb and Performer Vortec intake manifold. Should give you an additional 10-15 horsepower. Keep the stock ignition and exhaust manifolds and it will be very reliable. The Gen II Alpha drive will hold up just fine, they have a good upper gear set (with forged gears) and a stronger, course tooth, lower gear set than the older Alpha I drives.
Have fun!
Sincerely, Dennis Moore
www.mooreperformance.org (http://www.mooreperformance.org)

[502procharger]

dennis is the man when it comes to performance help but keep in mind 15 hp may net you 1 or 2 mph up on top. figure out if the cost is worth it to you. that is a respectable speed and it is a turn key fun boat no messing with it. just a thought

[mikev]

upgrade to a 4bbl and a bigger cam that will help alot.

[bigkatboat]

5000 RPMs, divided by 1.62 gear ratio = 3086.4197. 3086.4197 x 19 pitch = 58641.974. 58641.974 divided by 12" = 4886.831. 4886.831 x 60 = 293209.86. 293209.86 divided by 5280 = 55.532 MPH. 55.532 is PROP SPEED! Is your boat going faster than the prop? Do you have a larger prop, incorrect speedo, different gear? If you: had 5000 RPMs, 1.62, 19 pitch, you would be a winner @ 90% = 49.97 MPH! Good luck! eek!