SP 720 motor swap!

[cheapbeater]

Hey everyone, I pulled the motor apart on my new project ski- a 1994 SP 580, and found a bad bearing on the crank side of the connecting rod... instead of fixing that, i decided to do a 720 swap. I talked to Minnetonka4me, and he has an SBT 720 from a 1995 XP, he also has the grey box, carbs, and impeller for me.
I have a few questions, hopefully theyre not dumb questions...
-Will my manifold fit on the 720?
-will my exhaust breathe good enough for the 720?
-are there any other ''must haves'' for this project?
I pulled my motor out, and my pump. I have a pump rebuild kit coming as well as a new bearing coupler, and pto to shaft boot. I keep reading about a carbon seal, does my ski have one?
I am still unsure of how i am going to align my motor, but i really dont want to spend the money on a tool- hopefully the local shop will borrow me theirs.
Anyway, i'll update this with questions/comments as i go along for anyone who is interested...
Thanks for the help everyone.

-Dylan

 

[Bills86e]

Get the exhaust system includeing the thru-hull flange & seal. Block-off the old 587 pipe, its too small. Use a 2 3/4" hole saw. look-measure from a 720 '95 XP or a '96 SPX. Yes, you can use the carrier bearing & shaft combo. I suggest you ask MT if he can give ya a newer houseing
with the "stands, instaed of useing the belly-plate. Its mounting lines up the same but is more stable IMO. You will also need an extended ride plate, and a manual trim kit off an HX would be an asset also. Set and Forget!!!!! A 15/22.5 swirl is also a killer impellar, a must have! LOL

Bills86e

 

[cheapbeater]

i'll see what i can do about the exhaust- i think the one has is shot so i might end up looking on ebay... dont quite follow you on the driveshaft/housing, but i will probably stick with what i got since i already ordered the parts... ride plate? i assume thats the plate that sticks out the bottom of the ski under the pump..? will a longer one prevent bouncing or is it for some other purpose?

Thanks

 

[Bills86e]

It reduces porpoiseing conciderably. Your model may have a venturi with a second hole to angle the nozzel. My SP in my avatar did. (lucky me)

 

[derek]

definately get a 720 exhaust. also the water runs thru 580's and 720's differently. as long as you are shopping for exhausts, might as well shop for a perf pipe. stuff doesn't sell for much more than stock stuff on ebay. don't go too radical.