I am running at 650 HP with a 509 cube carbed.
But there isn't much that is stock.

 

I was looking into getting similar power from my ZZ502 but did not go thru with it. 620 from a 502 is very doable. Heads, cam, , lifters, intake......the right combo

Stock heads maybe but only with lots of work. I think you'd be better off with after market heads....AFR's

Talk with rmbuilder. No spin, no back yard BS. He can get you to where you want to be

 

If it were me I would go with 540 rotating assemblies, modern 315-325 CC aluminum heads (CNC port not necessary but a plus), custom hydraulic roller set up to run at 5700 RPM (RM Builder), Merlin single plane 4150 intake and a Nickerson Stage 5 850. That should get you 600 reliable HP!! Remember the stock merc CMI E-tops will start to poop out at 575-600 so in my .02 the 540 is the most sure fire way to go! Then, if in a couple of years you want more you can get some Sport Tubes or similar long runner header and see another 50 HP. Remember it is cheaper to do it once!!!!

Craig

 

I agree with Wette Vette...totally. He gave very real life cid vs exhaust vs hp information.

If you want to stay EFI I would seriously talk with Arizona Speed and MArine. They do a bunch of 502 / 540 EFI build ups using the stock Merc system. I also believe that the 500EFi uses Arizona Speed and Marine's intake manifold.

 

Selling the M3s with the fuel injection system may offset rotating assemblies very easily. The 557Kit is quite popular now with the 4.375" stroke. This type of CID with simple carbs and intakes will make your desired power with no problem. The increase stroke will also give you a nice flat powerband in very usable rpm for a boat.

The stock heads with port work will make this kind of power, but to invest $$$ in stock heads is a decision that you have to make. A good 300 to 315cc head would be an excellent choice.

 

I am buying a boat with M-3 Procharged 500efi. I don't want the Prochargers so they will be for sale this fall. I really want to stay above the 600HP mark but can it be done by:

Punching it out to a 540....
keeping the stock EFI system?
keeping the stock Heads?
staying with 87-89 octane fuel?

Is it possible to hit 620-640HP?

These engines will be our fall/winter project and am looking for some direction.

Just curious why you are dumping the chargers? Are the engines in need of rebuilding?

 

You can get up to about 650 HP w/o blowers.
Call Joey Griffin.

 

Re: Re: 500 EFI to 600+ HP (How??)

Just curious why you are dumping the chargers? Are the engines in need of rebuilding?

Yes, A company in Alabama called HESCO did the installation. I've spoken to them and from everything I've seen they have done a great job. Dash has oil pressure and temp guages, water pressure/ temp guages, boost pressure, flowscans for fuel and even pre-lubers for the engines. I know the computer was re-programmed and the fuel system switched to accomadate the needs of the Procharger. (Seems like the install was done with a blank check from the owner)

Now the problem......the motors have been "hurt". They have been run hot and "patched" recently. I'm told several of the pistons are discolored from the heat but the owner didn't want to spend the money to do a complete re-build. Not knowing what is in there I feel I HAVE to open them up this winter. The builder states it runs fine now, but he cannot guarantee it like it is. (Based on the deal I'm getting I'm perfectly happy knowing I need to open them up, I just want to do this ONCE!)

 

Oh wow... That sounds awsome!! Is that boat going to be that much more roomy and better rough water handling, than your last 'Mule???? Thought that is what you wanted?

Anyways... I want to keep close eyes on what you do and how it turns out, because I want to do the same with my boat.. In fact I may get the Prochargers from you if the price is right and have my motors at 650hp+, what is yoru resoning with the X on the PC's?

 

600 hp is possible with stock heads. I am pushing 700 with my stock GM 188 heads. We did do some work to them, but it was alot cheaper to do the stock heads then to buy aftermarket heads. I think possibly changing of the pistons, higher CR, new cam, head work, and remap your puter, you should be able to get between 575-600 reliable hp.

 

Oh wow... That sounds awsome!! Is that boat going to be that much more roomy and better rough water handling, than your last 'Mule???? Thought that is what you wanted?

Anyways... I want to keep close eyes on what you do and how it turns out, because I want to do the same with my boat.. In fact I may get the Prochargers from you if the price is right and have my motors at 650hp+, what is yoru resoning with the X on the PC's?

From 31 to 38, 502's to 500efi's, 1998 to 2002, every option available but genset. HELLO! :bigsmile:

The boat runs 74 stock, this one was at 8 psi running 95+, now at 5 psi it's still over 90 with 765 HP. Even though I have XR drives it's still gonna kill them eventually, the Insurance man is ripping me a new one because of the addl. power,and I expect the fuel economy to be lousy. Not sure these will fit a 502 because of the different intakes either, but figured I'd get about $5K for both sets once I take everything off.

 

Congratulations Russ. Awesome ride..

 

From 31 to 38, 502's to 500efi's, 1998 to 2002, every option available but genset. HELLO! :bigsmile:

The boat runs 74 stock, this one was at 8 psi running 95+, now at 5 psi it's still over 90 with 765 HP. Even though I have XR drives it's still gonna kill them eventually, the Insurance man is ripping me a new one because of the addl. power,and I expect the fuel economy to be lousy. Not sure these will fit a 502 because of the different intakes either, but figured I'd get about $5K for both sets once I take everything off.

Oh sorry was just going by what it says to the left over there... Yeah 38 is the Dealeeoo!! Sounds and looks like an extremely nice boat... But seriously I am planning on doing my motors as well this winter. I was thinking Mesa or Roccard to do my builds..

Hey do you have anymore pictures of your new ride? When do we get to see it?

 

You are going to want the bigger throttle body from Arizons Speed & Marine, or a similar product. I put one on my engine along with the computer upgrade.

http://www.azspeed-marine.com/hpefimothva.html

 

Just remember that when you port the stock heads to get that 600-650 HP You will drasticly shorten the life of the heads due to rust through.

Been there done that.

 

What's the highest compression ratio I can safely run 89 octane. I don't want to "have" to run 93.

 

Re: Re: Re: 500 EFI to 600+ HP (How??)

Yes, A company in Alabama called HESCO did the installation. I've spoken to them and from everything I've seen they have done a great job. Dash has oil pressure and temp guages, water pressure/ temp guages, boost pressure, flowscans for fuel and even pre-lubers for the engines. I know the computer was re-programmed and the fuel system switched to accomadate the needs of the Procharger. (Seems like the install was done with a blank check from the owner)

Now the problem......the motors have been "hurt". They have been run hot and "patched" recently. I'm told several of the pistons are discolored from the heat but the owner didn't want to spend the money to do a complete re-build. Not knowing what is in there I feel I HAVE to open them up this winter. The builder states it runs fine now, but he cannot guarantee it like it is. (Based on the deal I'm getting I'm perfectly happy knowing I need to open them up, I just want to do this ONCE!)

Do you know what happened that "hurt" them? If it had nothing to do with the prochargers I'd be leaving those bad boys on there(at lower boost) if they were done right, which it sounds like they were!

 

Re: Re: Re: Re: 500 EFI to 600+ HP (How??)

Do you know what happened that "hurt" them? If it had nothing to do with the prochargers I'd be leaving those bad boys on there(at lower boost) if they were done right, which it sounds like they were!

Yeah, The motors have been over-heated due to pitiful winterizing and running the boat with blown impellers. Supposedly none of the problems were related to the Prochargers. I hear that some of the Pistons are "discolored" due to the heat but were re-used at the owners request during the assembly (approx 2 weeks ago).

 

Re: Re: Re: Re: Re: 500 EFI to 600+ HP (How??)

Yeah, The motors have been over-heated due to pitiful winterizing and running the boat with blown impellers. Supposedly none of the problems were related to the Prochargers. I hear that some of the Pistons are "discolored" due to the heat but were re-used at the owners request during the assembly (approx 2 weeks ago).

If that's true if it were me I'd be leaving the chargers on! Sounds like you have a great platform already. Owner must not have watched the water pressure gauges!

 

I'd leave the chargers on. I'm not sure about CR and octane, but I have 10:1, and I run 93 octane.

 

What's the highest compression ratio I can safely run 89 octane. I don't want to "have" to run 93.

I would'nt go above 9.5:1 if you want to run 89. You may want to go alittle lower like 9.2:1 or 9.3:1. I am running 9.5 - 9.6:1 in my motors and I will only run 93. I could probably use 89, but for 10 cents more a gallon, i run 93. If you are going to run the pro-chargers, you should be in the 8.6-8.7:1 range and use good head gaskets. To high of a CR with the superchargers will cause to much heat and you will have damage in the long run.

 

What's the highest compression ratio I can safely run 89 octane. I don't want to "have" to run 93.

For no worries, stay with factory compression: ie:8.75:1. If you bump it a little by reducing block height during machining, this is fine and actually a little better.

A low compression 502 can still make prodigious power if the correct parts are chosen.

 

I am buying a boat with M-3 Procharged 500efi. I don't want the Prochargers so they will be for sale this fall. I really want to stay above the 600HP mark but can it be done by:

Punching it out to a 540....
keeping the stock EFI system?
keeping the stock Heads?
staying with 87-89 octane fuel?

Is it possible to hit 620-640HP?

These engines will be our fall/winter project and am looking for some direction.

One thing I like looking at is longterm cost and ones ability to fix something if it goes wrong. Fuel injection by far is the future but at this point in the marine world there are few people who can work on these systems. Even fewer that can work on modded systems. So I look at the "What if's". If your on vacation and something goes wrong what are you more comforatable working on or getting qualified help to work on. . .carb engine or a fuel injected engine. Chances are the carb engine can be serviced quicker and cheaper.

I think we should all take this into consideration. Now 20 years from now may be a different story.

 

I just can't take a 2002 boat/motors and put carbs on it. Of the 7-8 guys I hang out with I'm not sure any of them have offered the same advice. :confused1 I still plan on going to 540's with the stock EFI system. Was hoping to keep compression low, but realizing I'm not going to get close to 650 without it. Still hoping the stock heads will work but realizing those may have to be replaced too!

Look out for a parts sale! What are a set of M-3 Prochargers worth anyway?

 

SOmeone told me if you sell them to Rock Steady they are only worth 2000... lol