Valvetrain. Roller rockers, I believe crane roller lifters, better valves (so I'm told), and of course springs, retainers, and locks.

Oh, and paint color. :bigsmile:

 

Paint's the cheap part

 

Correct me if I'm wrong.
A 502 Mag is the same as an HP 500 with the exeptions of

1. Intake and carb
2.Cam
3 Exhaust

Heads , crank , rods , pistons all the same (good stuff).

Any other opinions.?Oh yes different oil cooler too

So is all I have to do to get more HP. I just need more money. :a6:

 

Oh, and paint color. :bigsmile:

So THAT'S why mine runs so good..Merc blue paint :laugher: :laugher:

 

Re: Re: 502 Mag to HP 500

So is all I have to do to get more HP. I just need more money. :a6:

My buddy's 242 has a 502 Mag and was thinkin' on upping it to HP500 specs for those few extra mphs


Boatally insane,

What kind of exhausts are they??

 

Re: Re: Re: 502 Mag to HP 500

My buddy's 242 has a 502 Mag and was thinkin' on upping it to HP500 specs for those few extra mphs


Boatally insane,

What kind of exhausts are they??

But why stop at HP 500 specs???

It doesn't really cost any more to get even more power out of it.....just a few different parts and some porting...

My exhaust manifolds are Keith Eickert's


Doug

 

Almost, heads use 2.25 intake valves and inconel exhaust valves and ignition module as well in addition to the previously mentioned.

 

I know. Throw in a 4.25 crank and get a 540. His idea was to simply clone a Merc HP 500 since Merc has alreay done all the R & D.
I was going to do the same thing but since I started with all new engines with all new parts the upgrade wasn't much ,if any, more. So I went the 540 route and have been phuquing with them for 3 years. Fine tuning can be a pain in the a$$
He has the opportunity to buy an HP500 intake ,carb and flame arrestor and was wondering what else would be necesary to complete the transition. The 540 rotating assy. would add another $1000 or so the project.
And like most of us , he's looking for cheap , reliable HP

 

I started out with a 502 Mag EFI....

I re-used the stock crank and rods
ported the heads and put in 2.25 and 1.90 valves,
a custom ground cam, Morel lifters, Crane rockers,
Victor JR intake and a Demon 850 Carb...along with a few other "little" things

Here's a link to more details if anyone is interested..
Engine build

It made 599.5 hp at 5600 rpm and 612 ft lbs of torque at 4800 rpm at the crank with "dyno" headers.
I put 63 hours on it this season without any problems whatsoever...


I originally looked for HP500 stuff but couldn't find any at the time...but then again I wanted to make a little bit more power than an HP500..



Doug

 

Boatally, What kinda speeds, @ RPM, and what prop, if you don`t mind.

 

Boatally, What kinda speeds, @ RPM, and what prop, if you don`t mind.

79.0 mph GPS at 5100 rpm with a labbed 28 pitch Bravo I

I either need to get a "shorty" outdrive or drop down to a 26 pitch Hydromotive as I'm not quite up to my peak HP at 5500 but I just ran out of money for this year...

Doug

 

79.0 mph at 5100 rpm with a labbed 28 pitch Bravo I

I either need to get a "shorty" outdrive or drop down to a 26 pitch Hydromotive as I'm not quite up to my peak HP at 5500 but I just ran out of money for this year...

Doug

Nice. 26P Should give you The extra RPMs.
I understand the $$$$$$ part.

 

I wouldn't mind doing some of this stuff sometime soon as well!! Great information....

 

79.0 mph GPS at 5100 rpm with a labbed 28 pitch Bravo I

I either need to get a "shorty" outdrive or drop down to a 26 pitch Hydromotive as I'm not quite up to my peak HP at 5500 but I just ran out of money for this year...

Doug

What Doug didn't mention is the ACCELLERATION of his boat!!!
It is a rocketship!!
===
Yes, the HP500 uses the Crane valve train parts, lifters and the gold roller rockers...

I also agree with Doug. Why stop with just the HP500 specs? Doug has a lot more hp than the HP500!!

I sure wish I had made a few changes when I redid mine!
Kent

 

I pretty much turned 502's into HP 500, roller train, bigger cam, the HP 500 carbs and a Victor Jr intake, and EMI Thunder exhaust. Gained around 7 mph from low 70's to 80mph.

 

Mud, pull it, work the heads, get a cam/spring combo, and stop WISHING!

You may not want to go 600hp, but you know you want more than 500...

 

Mud, pull it, work the heads, get a cam/spring combo, and stop WISHING!

You may not want to go 600hp, but you know you want more than 500...

I think he already knows the recipe - someone drove from far away to give Kent a taste that he can not scrub off.

:laugher: :laugher: :laugher:

 

Mud, pull it, work the heads, get a cam/spring combo, and stop WISHING!

You may not want to go 600hp, but you know you want more than 500...

My guess is would cost under 2k. He already has the good valves and right sizes.

So, headwork, cam, and maybe springs? Springs may be fine, but cheap enough anyway.

Hmmmmm. Maybe under $1500? :shocked: Depends on $$ of port work.

 

I think he already knows the recipe - someone drove from far away to give Kent a taste that he can not scrub off.

:laugher: :laugher: :laugher:

<a href='http://www.smileycentral.com/?partner=ZSzeb008_ZSYYYYYYBYUS' target='_blank'><img src='http://smileys.smileycentral.com/cat/36/36_11_6.gif' alt='ROTFL' border=0></a>

 

I think he already knows the recipe - someone drove from far away to give Kent a taste that he can not scrub off.

:laugher: :laugher: :laugher:

THIS IS TRUE!!!!
===
Actually, the motor runs so nicely now, that I will likely not touch it for quite a while, unless something breaks.

I hope to hit an honest 80 (at 78.4 now) with some TU help this winter, and that is really pretty fast (for me) in this microboat!

Kent

 

THIS IS TRUE!!!!
===
Actually, the motor runs so nicely now, that I will likely not touch it for quite a while, unless something breaks.

I hope to hit an honest 80 (at 78.4 now) with some TU help this winter, and that is really pretty fast (for me) in this microboat!

Kent

Just take you're toolbox out and you'll probably see mid 80's!!!! :laugher: :laugher:

Doug

 

I actually added weight and moved it around to get better handling at speed so I could stay in it and thus gain a little more. :bigsmile:

 

Just take you're toolbox out and you'll probably see mid 80's!!!! :laugher: :laugher:

Doug

Yeah, that thing is heavy!

A new kit like yours is on my Christmas wishlist!

Kent

 

I actually added weight and moved it around to get better handling at speed so I could stay in it and thus gain a little more. :bigsmile:

So you're literally a "sandbagger" :laugher:

Doug

 

Valvetrain. Roller rockers, I believe crane roller lifters, better valves (so I'm told), and of course springs, retainers, and locks.

Oh, and paint color. :bigsmile:

Any idea on what crane roller rockers and lifters specifically?