Prop suggestions new 351w

Ok, after reading this thread I'm going out and pull my prop and see what's on there. I'm getting 43 mph WOT with gps speedo. New tachometer says 4600 rpm. I knew the newer nautiques were slower and the carbureted 5.8 doesn't help, but in the right water conditions I can get 50+ out of my 73 with 48-4900 on the tach and that's a carbureted 5.0 with 1-1 velvet drive. Seems to me I can get the speed to rpm a little closer with the right prop.

oldscool wrote: Ok, after reading this thread I'm going out and pull my prop and see what's on there. I'm getting 43 mph WOT with gps speedo. New tachometer says 4600 rpm. I knew the newer nautiques were slower and the carbureted 5.8 doesn't help, but in the right water conditions I can get 50+ out of my 73 with 48-4900 on the tach and that's a carbureted 5.0 with 1-1 velvet drive. Seems to me I can get the speed to rpm a little closer with the right prop.

Those numbers sound a little optimistic on the 73... Not doubting your honesty but questioning their accuracy. Unless the engine has had some work done, 47-48mph and 4600rpm are the norm for that hull and power plant (and a stock 12x14 federal, or equivalent). A GPS and a known-accurate tach would tell the real story.

Whereas the 1600lb Skier will typically under turn with a stock sized prop (< 1:1 rpm vs speed) a modern hull will overturn by a significant margin due to its increased weight and larger wetted surface area. A 300rpm differential is actually doing really well (my 90 overturns by nearly 500rpm at wot with a stock sized prop). What doesn't seem quite right is the lower numbers- 4800-4900 and 45-46mph would be more typical out of that hull and powertrain (I'm assuming you have the typical gt40). Time for a tuneup maybe?

Tom, I went back and re-read your diary and your post... and Im confused, ha. You said you have the carbed 5.8 and 275hp- are you sure? I was only aware of the 260hp (non-HO) and 290hp (HO) carbed 351w's that PCM was offering in the late 90's. Any chance that 275hp is actually a 305 (5.0L) Chevy?

2000 brochure

If its a Ford, take a look at the end of the heads and see how many bars are in the casting... should be either 2 or 3. GT40 (HO) heads have 3, the standard heads have 2.

I do not care for the 13x16 OJ. An Acme would wake it up quite a bit. If you have the non-HO 351w or the Chevy 305, a 12.5x15 Acme would be my choice (most likely a 470). If you have the HO 351w then I suspect you have a little bit of tuning up to do, and an Acme 422 (12.5x15.5) should work best.

In regards to speed, the smaller hulls usually run fastest with a little bit of weight in back that allows them to porpoise. The faster (stock) 16' boats seem to porpoise naturally at WOT without any extra weight in back, and Ive seen a few flirt with the 50mph mark. A slight chop will run faster than glass calm. That 12x13 OJ is a good prop- much better all around than the original Federal (though top speed will be similar). Setting the speedo using the tach is a good way to get you in the ballpark if the tach is accurate- though most from that era were marginal, in my experience. Either way, it could still be off by a few mph, which is pretty common. A GPS would tell the true story.

Sounds good to me!

Let me know if you confirm which engine your '00 has... You've got me curious. Would love to see pics of that skier as well!

Check the heads just in case- then you'll know for sure. Numbers look pretty good if it's a non-HO.