Aluminum Engine in a 253
 

I have a 2000 253 Convincor, we pulled out the 502 and tried a little experiment. I replaced it with a 555 ci all alluminum, 6lbs boost procharger, EFI with a FAST programmable fuel injection. Running a XR 1.50, Imco hyd steering, still playing around with drive spacers to get the x dimension right but I think I'm close. The engine dyno'd at 830 hp, at 5100, over 800 ft lbs torque above 4000 rpm. The fastest GPS number I have seen so far is 101 mph at 5100 rpm, 34 pitch bravo 4 blade. Have to run alot of trim tabs to keep the hull stable above 80 miles per hour. I'm looking for some advice on IAC programming or any other Fuel Injection parameters that affect idle transition. The engine is a little temperamental when docking, wants to die when shifting from neutral. Any help is appreciated.

Post this question in the Technical Q/A Section and you will get more responses.

BTW....sounds like a handful of a ride !! My 253 runs 80 with a carbed 575hp and that is a handful at times. Good luck.

Sounds like a fun boat to drive, just wondering were you do your boating is it fresh water or salt, I am thinking of building a all aluminum motor, but i boat in saltwater.and don't have fresh water cooling.

Just freshwater. I don't have any experience with saltwater but I imagine that it could be extremely hard on the block, I think the offshore guys stay with steel even on their heads, the ideal thing may be a closed loop cooling system, I know some of the big guys have this.

I run closed cooling in salt water. In my opinion, it is the only way to go in salt.

Checkmate didn't make a 253 in 2000, they replaced it with the 259 that year.

253,259, not sure, they actually call it a convincor 270, but I think they are including the swim platform in the 270 designation.