How about buying a set of props that are 1-2" pitch larger than what you run normally, then have the bigger props labbed?

Can that be the best of both worlds (Cruise/Top End)????

I've heard of some labbed props loosing shape over time and blades breaking from being thinned. Any issue with that??

Going up 2 inches of pitch and Labbing to get the R's back is always the best move. Or if you are 200-400 from your top desired rpm. Going up in the pitch does reap the better of both worlds. The down side is only that a small amount of acceleration can be lost going to the higher pitch. However the Labbing does bring most of it back.

Pat,
What HP are the 502MPI's? Just wondering, I am rebuilding to around 425HP this fall, I'd be satisfied to see 60 even (knowing that I am 2-4 mph down for the classic hull).

My engines are 415 HP @ the prop. 500 hours on them.You should be over 60MPH with that power.I'm not sure what props would be best for the traditional hull but I'm sure Brett wil know.

Thanks for the info Pat. I'm running 21's now (embarrassing as it may be).

Can't wait to get these motors out......about 60 days to go!

PJ. What speeds do you top out at and what power do you have currently? It will be interesting to see your gains. One guy I spoke with had 390 prop hp/502s, traditional SC hull & ran 24 Hydro quad 4s.He turned 4500rpms. Sounded a little low to me. I was shooting for 4900.

Well, I'm too messed up this summer to even really give good numbers.

In flat water, no wind, I can get 48 out of it. Blew one motor end of June, replaced that one with a mag, that side blows out badly after about 4500 rpms (spinning 21's)

I have 2 GEN IV 7.4 MAGS that will be built a little beyond the old merc 420HP specs (making them full rollers), hoping to see around 450-460 HP per.

I will have to play around with props quite a bit I imagine, I was thinking I'd be into a 25P, not sure what that equates into a 4 blade.

I have a buddy who runs a stepped hull, he has cleavers, a lot of other heavy boats I have seen lately have 4 blade, is there a reason for that?

I'm honestly more interested in cruising speeds, I would be happy to see anything over 40 mph at 3400.

The OEM valve covers on the motors going in this fall are telling me the max operating is 5000.

4800 to 4900 would make sense to me topping out.

http://www.offshoreonlyclassifieds.c...o20110-en.html

1 down or 2 when you add a blade?

Pat, you ever had to replace your drive/tab indicator cables?

That's another thing on the winter list.