bajaman

A few weeks ago I picked up a pristine 252 Islander, with the base 454 MPI, Bravo 1 drive with 1.50:1 gears. Running a 21" Revolution 4 prop I get 52 MPH @ 4400 rpm, this is GPS verified.

My other boat is a 208 Islander with a carbureted 454 and it'll run mid to high 60s, I've had that boat for 28 years and got used to that speed. My goal is to get the 252 up into the high 50s - low 60s...can I do that with simply swapping in a 502 Mag MPI? I've seen some reasonably priced, low-hours engines for sale from time to time. From what I've seen and been told, this should be a 'plug and play' option...right down to the engine harness and Silent Choice exhaust.
I have a dealership brochure from 2001 that shows that boat as having an option to be equipped with a 470 hp HP500 EFI...but there is a footnote that indicates the Corsa Quick&Quiet exhaust isn't compatible with the HP500...? Not sure why.
Basically I want to pull out the 454, drop in the 502 Mag, hook up fuel, power, and existing Corsa exhaust and go. Would it be that "easy"?

Note: meant to say '502 Mag MPI' in title...

jetskidrewski

Corsa Quick&Quiet was likely not compatible due to backpressure.

Baja Rooster

How important is the silent choice for you?

Fwiw, 500hp at the crank pushed my 272 Islander with 5 adults to 63 GPS. A fresh 502 oughta really bring it alive.

Griff

You will probably pick up 3-4mph or more swapping to 23 Mirage Plus prop.

Baja Rooster

I tried two M+ props on my 272, one labbed and one untouched and the Rev4 was identical top speed and way better everywhere else. I’m just sharing my experience. On the Cuddy models the M+ is the way to go.

obnoxus

+1 I had a worked/cupped M+ 23 and by far the best of the many I tried on my 272 w/ 502MPI with a 500 EFI cam and Gil manifolds.

All that being said. I would have left the stock 454 MPI in there if I was as smart then as I am now LOL

bajaman

I never use the 'quiet' feature of the exhaust so...not important. The thru-hull only on my 208 is much louder, more of a staccato 'bark' to it, so that's what I've been used to for many, many years, lol!

63 on your 272 with that load is pretty impressive. I'd be happy with that or a scosche more on my 252!

Is a $10K budget reasonable?

bajaman

Thanks.

Interestingly, the brochure footnotes indicate that Captain's Call is available on the HP500, or thru-hull only. Could the Captain's Call be that much different than the Corsa Quick&Quiet? Assuming going with the HP500 it would just be a case of ditching the Corsa parts, capping off the Y pipes, and running 4" hose to the outlets?