The hub kit you should be using should have 4 flat bushing rubber that don't come off and uses 3 washers and a nut on the outside of the prop

That is the hub kit I have. Installed by Performance Marine, who installed the shorty. And yes I have the "cupped" washer in the right position and oriented properly.
I can move the Turbo 1 for and aft (much more than the Bravo 1) but more importantly, side to side.

I would look into that!

Great thread! Read a lot of what to look out for!

My boat handles great now with the -2" shorty....Better in every respect. No downside whatsoever (except maybe the $$). Comes out of the hole good, even pulling a water skier.
Saw 71 mph (GPS) the other day, and I'm 2000' above sea level (non HO 496)
Going to try some different props next year to see if I can pick up another MPH or two.

Mark

That's awesome Snave! The one I'm currently looking at I need to consider the drive itself. It's a 96 and with an engine combo I'm considering mid 70's is my ideal speed. Still haven't seen the lower unit yet so it may be a deal breaker depending on shape and would be nice if it was a -2 IMCO really depends on how much money I'll need to get it where I'd like it to be satisfied. Plan to fail or fail to plan!

It would seem the -2" drive is a speed gain of 2-3mph. My 96 with stock 502 and stock B1 will run 70+mph any day of the week and 73mph running light. I have no doubt I'd gain the same 2-3mph with a cam and carb change +50hp... I believe to consistently top 75mph you will need 470hp with a stock length drive or 420hp with the shorty... I would also plan for at min a single external ram "add on" steering system.

I get 75-76 gps with my 496 stroker spinning to 5000rpmake. This is with 500hp on the dyno. The drive is stock length just a nose cone on it. Depending on life I will be adding the shorty withing the next year or 2. Basically Pat I think your numbers are realistic for real world is.

I gained 4-5 MPH by adding the shorty to my non-ho 496.......But, that's comparing what I was seeing on the stock Livorsi water speedo to what I'm seeing now on GPS....I know, I know, I should've GPS'd it before installing the shorty.
I'm not sure whether the stock water speedo's typically read higher or lower than actual speed.
I was turning the Bravo 1 26P around 4500-4600 RPM. With the shorty I'm turning 4900-4950 RPM
From a seat of the pants feel.......The boat fly's now,

Mark

Mark, your wife back in the boat with you?

Ken

Happy to hear it worked out. I have a lot of respect for performance marine

Yes!!

My numbers are nearly identical with stock drive and 25p Rev 4. From last Thursday, I saw 71.2mph on my phone GPS @ 4900rpm.
A stock 26p B1 prop is about the same pitch as a stock 25p Rev 4. We are seeing about the same slip/efficiency.

As for a pressure driven Livorsi speedo, if liquid filled and using pito in the drive, they are pretty accurate. At least the one I had in my 280 Velocity and the one a bud had in his 29 Fountain were on the money...

To quote you.......Better in every respect. No downside whatsoever

Glad to hear.

Ken

If that's the case then I gained a solid 5+ MPH with the shorty. The most I saw on the stock speedo was 65 MPH (at the 2000' elevation)

Mark

Nice numbers for non ho boat @ altitude!

Mark, I have a 2004 40th anniversary? That is what I have

Peter

Is that what you have?

Yes 2004 Anniversary in Yellow