500 HP build
 

i have two 500 HP's and was wanting to build them to get more power and speed and wondering which way to go?

Call Bob Madara.

Blowers or heads/camshafts or whatever you want Bob can help.

5856548583

x2

I'm interested in researching options for my hp500 as well.

What was your budget and goals?

Looks like new heads and cam can get you over 600 hp, heads $1600, cams are ? and then what else?

What would one expect in labor to put in a new top end?

I spoke with Eddie Young in Tn. YOUNG PERFORMANCE found him to be very easy to talk to and a mountain of information, I'm sure he could help with some options

Ron Potter can do a lot with these motors too.

What if you want to reuse the HP500 Steel heads, (running in salt water) and just have them ported and massaged.....

Bob Madera helped me with my HP500 build. Went with AFR heads, custom cam, Willies carburetor. Bob has perfected this combination. give him a call. He is a great guy to deal with.

I also agree call Bob M. The new AFR 290 ovals would make a killer head for your combo. I have a Marine Kinetics Cam, AFR 265 Ovals and a Pro Systems carb all from Bob and I'm making 525 hp out of 439 CI. The same combo in your boat would make around 600 hp.

Since this is the "boating on a budget, do it yourself" section, how much more HP are you looking for?

You could easily do a cam upgrade from your current 731 to the 741 or even the 651 for minimal $$$ investment, then some good heads (bigger investment) and you should be around 600 hp.

If you want to tear into the engines (even bigger investment) you could go up to 509 cubic inches and increase the compression to 9:5 to 1.

Just finished mine.

Flowed 358 @ .700 int, 231 @ .700 exh.
I blended the bowls, radiused the SS radius and worked the guide bosses on exhaust. Not a lot of work. Left the runners alone.

Put in 11/32 valves (.100 longer)

5 angle intake seats, full radius exh seats.

Milled .010

One thing to remember, HP500 heads are 088's, but are not 118cc. Merc worked the chambers out to 122cc's to keep compression down below 9 to 1. I should get around 575 HP, and over 600lb torque.

Bullet proof motors if done right.

Thanks for all the data guys, I'm torn between using my present heads, and buying som Alum heads, (concerned about saltwater corrison issues...)
Dean

If you go with Aluminum, have the water passages hard anodized and you'll be fine. I think its about $100 to have that done.

I have a HP500EFI Vortec M3 supercharger,EFI,intercooler,pulleys,remapped ECM for sale
[email protected]

That is a good idea.
Thanks,
Dean

I went the 509 ci route which increased compression. Cam, Pro-form 950cfm carb w/ super suckers. Kept stock heads and ended up 589hp. Love the new carbs. Starts and idles like a fuel injected engine

Really nice #'s for stock heads!:drink:

That's pretty impressive.. Now you have to give us some details. Head work, Cam, etc. Build sheet and Dyno sheet would be even better :drink:

:food-smiley-007: More More!

Tthe Edelbrock (marine) heads are anodized

Marine Duty Performer RPM 454-R

Heavy-duty, 1.89" Inconel exhaust valves provide added durability for marine applications
Hard anodized black to protect the aluminum in the harsh marine environment
Sold with valves only to allow for valve spring choices
Match with an Edelbrock Performer RPM manifold, Performer Series 750 cfm marine carb and Performer RPM cam for proven performance
Smaller-than-stock 11/32" valve stems promote excellent flow and lighter valve weight

I have a set of the Edelbrock rect port marine heads ..part # 61559...they have the comp 924-16 springs..around 25-30 fresh water hours on everything..let me know if your interested

The work was performed by Ellison Engines in Cincinnati and Mike Haste. The cam was a custom grind (not too far off from the 525 cam specs), we scrapped the stock ignition and went to the Crane HI-5. Motors completely tore down and balanced. All parts turned and touched. .030 over with mini dome pistons.There was no head work done other than a valve job, new valve springs. Stock crank and rods. Made 589hp @ 5600rpm, 586lbft torque at 4900 according to dyno sheet. Next year I hope to go the next step of alluminum heads. I'm not a motor head so this is about all I know.

Contact Niceguy, he did 2 with Bob's help and they dynoed at 721HP.

I had the same worry and I know guys have had problems but could not pass up a good deal on the heads I am using. I have run them for 4 years in salt and when I tore them down a few months ago I saw nothingh indication a problem. I am a freak about flushing though.

Me also, so maybe it won't be a problem.... I have used KE headers in Salt before on a another HP500 for 7+ years and had no problems with them, once again , flushed each and every time, for at least 10 minutes...
Thanks for all the tips guys, please keep them coming.
Dean

Sounds like you got the right combo. How do the motors run with those big Carbs on them? What props are you running now?

Not to Threadjack, BUT.......

Sorry for all the questions. I hope to have mine on the dyno next week, and it's pretty close to what you have done, so I'm trying absorb as much info as possible.

Doesn't the stock ignition have a rev limiter built in?

I belive i the stock limiter is either 5300 or 5400 RPM.
As long as it is current enough to have the GM knock sensor.

Motors run great. I couldn't be happier. Not too bad on fuel either. We struggled with idle with the stock carbs which is why I opted for the new ones. Now it idles and starts like a Fuel injected motor. I have a T/S 38 Cig and hit 87mph on GPS speedo. Lot of guys said i'd be lucky to hit 80 with that heavy of a boat...so was a pleasant surprise. B1's with 1:36gears. 26p Bravo prop. Drives/Gear change/ Prop change hope in the not too distant future

very interesting....... how much compression?

I can get you one of these if you want it. This one is sold and going in a single Eliminator, but I can fix you up with one just like it.

http://www.youtube.com/watch?v=TaZru-Mo9wg

when i picked up the boat the first time I was talking to technician and mechanic and I thought they were kinda off. I do not think Leon even knows whats going on over there.