I own a 1998 25'3 checkmate convincor. it has a 454/300 HP 7.4L motor now. I want to upgrade and get this boat to run say low-mid 70's I was looking at a create 502 mag mpi. any idea's? If i go with a fuel injection motor do I need a engine wiring harness? or fuel pump relay ,wiring etc etc?

thanks

Forget the EFI!! For the money you'll spend converting you could build a 550-600hp Carb motor.I have the same boat and run 75 with 550hp.You can either build up your 454 or consider a World products 540 crate motor.If you buy a GM 502 crate motor for a good price you can upgrade the cam,intake,carb & add roller rockers and easily get 500hp.
Have fun,Mark

You will need around 500 to 550 hp to run mid 70's GPS. Might search the OSO classifieds for a HP500. Or you can build one but be sure you build to marine specs, not automotive. I,m getting low 70's with 450hp in a 229 but it only weighs 3200lbs. Good luck, you can never go fast enough!!

You don't want to try to build your current motor. Pull it...Sell it...and search for another. Like Outlaw Mark said - check out World's 540....Probably put you where you want to be.

is anyone running a world motor? What is cost ? I can't open damn page I don't have adobe my old computer

Checked out the World 540 in my Summit catalog. Price is $7495.00 + shipping. Not a bad price for 540 horsepower BUT it says " Not for marine use " in the ad. Is it still ok to use in your boat ? anybody tried it ? Why does it say this ?

I think you can get a marine version of that motor from World Products. Im sure the "marine" intake has brass water jackets and brass freeze plugs in the block. Id bet the cam is the same though. You may to see if it needs a different exhaust system to keep reversion away.


Eric

Cap071
Wiring harness is different and I don,t think you need to add any FP relays if you go with a 502 mpi.This power will get you to 70mph on speedo.
Try http://www.1800runsnew.com/gm08.htm

STAY AWAY FROM THOSE 540 WORLD PRODUCTS ENGINES YOU WILL NOT BE HAPPY.........TO GET INTO THE MID 70'S WE WOULD INSTALL A 450HP GM 502 CRATE ENGINE WITH GOOD EXHAUST AND INTAKE/HOLLEY CARB/CONTROL MODULE...WE HAVE DONE ALOT OF THESE WITH GREAT SUCCESS VERY RELIABLE....IF YOU WANT MORE PROCHARGE THAT....
WE ARE A CHECKMATE DEALER (KUNKEL'S MARINE) AND HAVE DONE ALOT OF WORK ON 253'S.

JOJO you had bad luck with the world motors ???