What prop for Pro Charged 253 Checkmate
 

1997 Checkmate Convincor 253 / Procharged 502 with Lightning Headers / Bravo XZ 1.36 ratio. Does anyone have a similar set-up ? What size prop are you running?

What kind of HP are we looking at?
Do you have any idea on the wet weight of the package?

Brett

700 HP, Wet weight would be 4500 lbs. Thanks Brett you steered me right on my last boat.

Ok,
You realize with that HP to weight ratio and hull design you are looking at a potential 100 mph set up.
You would need to turn a 30 pitch propeller at 5400 rpm with a 12% slip.
I'd bolt on anything in the 28 to 30 pitch range to get a base line and we can discuss the results and go from there.
Call me if you need a test propeller and we can help you out.

Brett

A 253 with 700hp will run right around 85mph, what rpm do you need to turn? anything else done to motor?

id suggest 26p bravo 1...... @ 5400 and 85mph a 26p will be around 13% slip

Motor is bone stock with the lightning headers and pro charger, intercooler at 7 lbs. I am currently running a 30 pitch Bravo1 prop which seemed about right to me because I assumed I had a1.50 ratio outdrive. But when we opened up the out drive and it was a 1.36 it made me second guess my prop size. I have owned the boat a short time and really have not had it on any good wide open runs yet. I believe I still have the stock rev limiter which is 5150?

At that rpm you still may be slightly over pitched, get some good runs in and see, but you should be somewhere around 85mph

hows it running?

My drive is a 1.5 ratio. with the 30 Pitch I am about 82 mph at 5000 rpm. That where it starts leaning out. I am upgrading my fuel system right now.

Where you able to get it dialed in? Does this hull have the notched pad/transom?

Yes notched pad / transom. Yes I did get it dialed in. Took care of all the shortcomings in my fuel system. Best run was 86 mph with the 30 pitch prop, approximately 5200 rpm.
Then blew the stock head gasket. Motor is torn down on a stand in my barn now,

You might want to ask Mr Gadgets...I think he has a lot of knowledge on the 253 and 259 hulls...I agree with Sabo...85mph with 700hp is about right...and very fast for a 25 footer...Extension box, bulletproof steering system, and a lot of HP is needed on these hulls to get into triple digits...from what I've read people saying about the really fast checkmates...Keep up the good work and keep posting results...I love hearing the modifications and changes people make.

Mr. Gadgets rebuilt my drive last winter. I stopped into his shop when I dropped off my drive off. Very meticulous shop and very meticulous work on the outdrives. We spoke at length about checkmates.

I was hitting 86 before I blew head gasket. I am planning on rebuilding in the same cofiguration. I am happy with 86 for now!

86 is on the money for that HP. A good friend had almost the exact same set up in a 1996 253 and I ran the boat to 83.X the first time I drove it with a labbed 28 or 30 Bravo. It had a little more in it but with only 3 minutes of seat time I wasn't comfortable pushing it further. Plus the windshield caused the wind to blast me in the face and my eyes were watering horribly. LOL That was my only complaint with that boat. It handled great.

Yeah, I wear goggles when I really crank it up.

Update on this boat. I was out the other day running the fresh motor. Slightly more horsepower than before. I had 6 full grown men in the boat and trimmed very conservatively. I was at 5500 rpm and 82 mph. That was on a real short run so it does have a little more yet. That calculates to 21 percent slip. I am around 14 percent slip by myself and trimmed up.

According to these calculations the boat should run somewhere in the 90"s now.