Prop for 23' Inboard Re-Power

[aldo]

I'm also very interested in this discussion. We are a rare breed as there were only about 80 inboards produced in the 70's and we are among the last ones standing, or floating I should say.
Mine is a 1976 that originally came with a Ford 351 which was tired by the time I got it in 1992.
I re-powered in 1995 with a Marine Power 350/260 hp with throttle body fuel injection. I tried multiple props and settled on the 16 x 15 with cup as showing the best numbers. Fuel consumption has always been 6gph or less.

[GetReel]

I have A 454 Marine Power 330 MPI / FWC installed 2001. Actually just rebuilt last year. The original was the Ford 351 LH 1.5 tranny and burned about 8 gal per hour per orignal owner.

My numbers are about the same as those most have, 3250RPM cruise gets me about 19.5 - 21.5 knots depending on load and wind/tide variables. I hit the top end at about 30 knots at 4600/4800 RPM WOT. I can cruise at about 3400/3500 at about 22.5 knots but thats not her sweet spot. I dont really track fuel burn much but I would ball park 12 gal per hour full load for the big block appetite. I can go about 35 off with spare fuel leftover and make it back by keeping her at 3000 and 19 knots on the way out with full load and not pushing too hard, drop in lines early, troll back in etc.

I like the 4 blade for improved hole shot and I think also improved slow speed handling, although, we all know backing this boat up can be humbling. I just had my prop reconditioned and last year I did epoxy barrier coat job and I think I have picked up 1.5 knots on that.

Good Luck.

[Gary Hill]

I stand corrected the prop I have is a 17 X 17. My fuel gauge at 3100 read's I'm using 9.5 GPH. I do turn 4600 RPM.
I guess being retired and old I need to double check things more often.

[MarkR]

Mine is a '75 Sceptre inboard, Marine Power 350 - 4B Carb 260HP

16 x 16 cupped

2700rpm - 20knts (most economical cruise - I think)
4000rpm - 30knts

[joshz]

I have 78 23 sf inboard- 350 mercruiser -260 hp- bw 1.5=1 tranny, 4 brl.
16x15 cupped

2800=21kts=8 or 9 gallons an hour depending on tide
4000=30kts

I don't think it gets any better unless u have 330 mpi even the 454's do not have anything on the 350.

[Gary Hill]

I know the 350's are lighter then the 454's and I do get a little rumble in the bottom with this prop. The 350 fuel injeted when I bought mine was 330 HP @ 4800 RPM and my 4 barrel needed to turn the 4600 RPM to open about 3400 RPM and I have a fuel monitor and a GARMIM 2210 also tabs and I try to stay under 10 GPH since anything more is about when the 4 barrel kicks in and I hit 37 top end (MPH), it handles way better then the 233 HP 351 I had. The hole shot is great.

[riprunner]

I should hopefully be back in the slip next weekend. I took some extra time doing things this spring I know I wouldn't when she's in the water. Last fall when I did a test run after the prop work I think I was turning 4500-4600 rpm. I will check my top again to be sure. I think I need to tweak it to run 4800. I am running a newer MPI with big hp, but I also have a very tall t-top with that is fully enclosed with a 4 foot open array so I'm sure I have more drag than most.