Hey Chris,

First, is your avitar picture taken at Lake Billy Chinook in Central Oregon? We go there all of the time.

I am pretty sure that I had the first Heat in Portland.

Our stock 502 is at almost 500 hours and I am thinking of working on the engine this winter.

I don't want to go 100 but I would sure like my Heat to be an 80 MPH reliable boat. I have watched your posts for a couple of years and you seem to have tested - just about everything available for purchase in the marine market.

So if you have a minute. Horsepower range and drive etc. for the 80 MPH mark would be awesome.

Thanks,

stock stoutman in Portland!

Stoutman,

The picture was taken at the sand bar, on the Columbia river.

As to the second question...
600 horsepower is what you need to get going 80 mph in a Heat.
I don't know what year 502 you have... but the easiest route there is probably by installing a 4.25 stroker crank into your motor when you re-build it. This will make it into a 540.

You will need to set your outdrive depth at aproximately 4.5 inches. This measurement is taken from the lowest point on the keel...to the center of the propshaft.

For props... I would recommend either a stock 28 Bravo spun at 5400... or a Merc Lab 30 spun to the same rpm. The 30 will be faster...but is a more expensive prop.

Hope this helps.
If you have any more questions... feel free to give me a call or ask here.

Chris
206-235-4545

I had the same dilemma last winter. I had a 415 hp 502 in my 2000 heat with 400 hours that was making some valve train noise. I had the motor completely rebuilt using 8.75:1 blower pistons, a 525 cam, Dana marine exhaust, and a top mount 2.3L whipple. I'm around 650 hp and am very close to 80 with a 28p bravo running 5100 rpm. A labbed 30 should put me 81-82. Like Chris said, pay attention to your drive height. Most heats running up till 80 need a 1" spacer. Mine was a handful after the hp upgrades till I added the spacer.

Hey Chris,

I'm Brad and I am thinking the following on the rebuild. Give me your thoughts.

Fresh the motor.
Dart heads.
Pro-charger with intercooler.

Here is the issue. Different intake as the one on the 502 chokes the engine. Thoughts and suggestions here are what I need. AND completely unsure of which direction to go with this.... Holly... ?? I know I am showing igorance here... Buy Mercury Racing someting?? Help.

R and R the exhaust (keep in mind we still want to tow the girls and their friends on the tube (below 50))

I would really appreciate everyone's feedback on this task. I don't want to build a machine that is fast and not useable for family life and I love turnkey. I've built a few Camaros that always needed attention. You know - when they need to start!!

Input is appreciated and respected!!

I hope everyone has a great Labor Day while it is 62 in Portland tomorrow.... feeling like pulling the engine and putting the boat back in storage...?

Brad

The easiest way to get horsepower is to bolt the Whipple kit on your motor. It will get rid of the lousy intake, is a complete kit, and you will have a 82+ mph boat with turn key reliability. 05R1 aka Ned, put a 2.3 whipple on his 502, and we got the boat going 82mph on friday. He scabbed this kit together off of buddies and craigslist... and the boat ROCKS!

Here is the formula for a sure fire...reliable setup... You should easily get another 500 hours out of this setup.

Rebuild bottom end with blower pistons
Set compression about 8.5 to one
Keep stock heads
Install 525 cam (RMBuilder aka Bob Maderia, can get you an exact copy 585-654-8583)
Install Dana exhaust (best bang for the buck!)
Install this kit: http://www.whipplesuperchargers.com/...sp?ProdID=1150
Talk to Dustin Whipple at: 559-442-1261 for any technical questions about your setup
Put a 1" spacer on your drive (you can find them used for about $100)
Run a Merc Lab 30 pitch prop (a stock 28 Bravo will work also...but will cost you about 2mph)
Drive boat for 400-500 hours (top speed will be between 81 and 84 mph)
Smile alot!


I agree with you on the Heat. My boat does consistantly over 100mph, and I can still pull my kids easily on an innertube or take the whole family (and kids friends) out for the day and have fun. A cat can't touch this thing for versatility!

Chris

P.S. If you need someone to do the motor for you...or recommendations...give me a call 206-235-4545

Hi Brad,
If you want to stay naturally aspirated, I think your 502Mag rebuilt to a 540" (4.25" crankshaft and .030 overbore to 4.5") will get you pretty close. You'll need new forged pistons (8.75 CR) and rods. You are correct about the restrictive intake and small CFM throttle body on the stock motor. There are several nice EFI intakes with large bore throttle bodies that would be a big improvement there. I think your heads are rectangular port GMs, which aren't bad, and could be upgraded. No doubt Dart Pro 1s or Iron Eagles would be better.
The 525 cam or a clone would work great. And of course you'll need to upgrade your exhaust. I think you would easily get around 600 (stock heads) to 650 (Darts) HP out of this combination.
Then if you wanted to supercharge (now or later), you would have a good strong bottom end already built. Personally, I like supercharged motors. As Chris says they can make very nice horsepower with good reliability. The Whipple 3.3 or 4.0
would top this motor off nicely.
You will probably need some rigging upgrades (hydraulic steering/spacer/beefed up drive/propeller) to go along with the additional horsepower and speed.
The good thing is you have great hull to work with. They handle very well with additional power.
Regards,
Steve

Chris and Steve,

Thanks for the input. Which drive do you think would be adaquate for that installation. XR? I just have a standard bravo now.

Thanks again.

Brad

A well built XR will handle 600/650 HP no problem.
Actually they will handle a lot more if you service them regularly. Oil change/magnet inspection every 20 hours, or after every poker run, and partial teardown/inspection (gears/bearings) every off season.