question on imco 3 inch shorty
 

Has anyone ever tried a 3 inch shorty on a non step v 28 heat. The boat is a 1998 heat.

My friend Butch is running a -2" on his '96 with a B1 4 blade.
The boat still has plenty of lift, and planes off without cavitation, so a -3" might work. It's overall handling characteristics (less porpising, high speed stability) are better too.
It also depends on how much horsepower you are running, and what type of propeller. The higher the horsepower to weight ratio of your boat, the higher propshaft height you can get away with. You may have to run a propeller with larger diameter, more blade area per blade, or more blades (like going from 4 to 5).
A 3" change in propshaft depth would be pretty radical.
I would try to find one to test before laying out the $$$.
Regards,
Steve

thanks

i was thinking of going with a 3 inch with xz drive because i can get a deal on one , My brother in law is SLV Villian he has a 2 inch speedmaster he planes out really good, ill keep you posted thanks for your info

Something to think about...........you can use a 1" spacer on the -3" shorty if it does prove to be too high, getting you back to -2" net propshaft depth.
How much horsepower are you running?
Good luck and keep us posted with your progress.
Regards,
Steve

Right now im running a 500hp carb, bravo 1 outdrive with 26 bravo 1 prop, I purchased a procharger system that i half to put in .They say at 5psi 710-740hp well see and i have the 3"shorty i half to install also i dont know were to start for a prop

3 inch shorty
 

one thing to remember is with a three inch shorty you have to cut the rear of the drive off to clear the blade but this may help the older heats they did have a very deep x demension

i just put a 1'' spacer because the boat did not want to plane and yes i had to cut the back off the spacer looks like the drive was already done was very easy to do. will try out the boat this afternoon will let you guys know how i do

I'm in the same situation as you, except my hull is a '97 and I have a 502 Magnum MPI. I also have an M3 Pro Charger awaiting installation and like you, have been thinking of raising the X with a shorty gearcase, so I'm obviously interested in how your experiment turns out. I am so spoiled with my 21' Superboat/300X because I can make the same adjustment in a few minutes with a wrench.

works really good planes out good i still have to get a few things for the procharger i just want to ride the boat the weather is awesome

Did you see any more speed?

So there you have it guys, a -2" shorty lower unit seems to be the ticket on the 1999 and earlier pad vee Heats.
Keep us posted with your progress.
We are working on Mayor McCheese's (aka Butch Fletcher) Heat's engine now.
We'll let you know how it goes.
Regards,
Steve

I would be interested in knowing the improvement in the MPH. Better handling is great, but picking up a couple MPH makes the investment that much sweeter.

I hear you, but there are variables............
That's going to depend on on your horsepower and current speed. With a stock motor, I don't think it's a cost effective mod. Most of the 502 MAG motors and boats are running 65ish, and they seem to have good lift and acelleration.
The factory set them up properly for the HP and propeller technology that was common then.
With a 550+ motor, it should help. It's like a nose cone. If your not running 80+, there's no need to fool with it, because the stock lower is fine to that speed. However, it does become more efficient, the faster you go. The same with a shorty. In other words at 65, don't bother. At 75, maybe, depends on how the boat is handling. Porpoising is a symptom, as is chine walking. At 80+, yes..........
We have messed with Butch's motor so much I can't really give you a back to back (stock lower to IMCO -2" lower) comparison on MPH. As far as handling goes, the porpoising is pretty much gone, it doesn't chine walk over 80, planes off like it did with the stock lower, and still has good lift.
BTW, that's with stock cable power steering. With full or partial hydraulic, it would be even better.
Maybe one of the guys on this thread can tell you how theirs compared on MPH.
Regards,
Steve

I am still messing around with different props and stuff with my shorty It really helps with the porpoising and such.I have yet to see a good gain with the merc shorty but it got hot and humid as soon as i put the shorty on.Powerquest is my brother in law we both have older non step pad bottom heats, and we both have shorty's