How about everyone chime in on boat lenght powerplants and cruise speed aswell as wide open throttle speeds. also the boats weight if you really know what it ways.

I can't really answer until spring. I just got her and there was a major issue with the port engine. It would plane easily and felt like mid to upper teens. The starboard engine would hit 4150 WOT and I am swinging 19X16 Props. This is a 50 fter with twin 350 Chevys rated @225HP

Got my GPS software. Using Fugawi ENC. Uses NOAA standard maps in a word, Awesome. The burns runs 13 MPH@3100 15 Mph@3300 and a tad over 20 MPH@WOT. The engines appear to be 260 HP Chevys. The port motor is better but oil fouls number 1 cylinder after 1 1/2 hour of run time and just hits 4000 rpm while the other does 4150. The boat is a 1976 50 FT.

Swap a quart of Rislone for a quart of oil and your fouling may stop. If that does'nt do it give it a shot of Restore.

Rislone, Restore, WD40, Miller Lite and Jim Beam keep the old farts running smooth.

Thanks. I actually have two issues. one: I am not sure of the true RPM. The boat has three RPM "devices". There are the two round Tachs, and ensign digital that shows both RPM and sync and a small guest sync meter. So I sync the engines with the ensign, the round tach shows the port @300 rpm faster. The sync meter shows the port as slow. So in my postings I assume the ensign is the most accurate and the port engine truly turns less RPM. If the round tachs are correct than the power output on port is fine. Issue two is of course the oil burning and fouling plug. I will take your advice at least for this summer. In my experience when a Chevy is fouling plugs the valve seal is bad. Around here you can have Chevy heads rebuilt for about $100 and put the whole thing back together for about $50 in gaskets.

You can install the valve seals without pulling the heads. 2 valve cover gaskets and 16 seals and your ready. 3 hours labor.

I HAVE A 50FT. WITH 318 CHYS. AT 2000 RPM HITS ABOUT 13KT.

HAVNT RUN AT WOT SO DONT KNOW WHAT IT WILL DO

ANY IDEAL ??

My boat is a 31-footer deep-vee hull, 16,000 lb.
Engine: 8.1 liter gasoline (single engine vee-drive)
Reduction gear 2.06:1
19 x19 prop.
Wide open throttle is 4300 RPM and gets 19.3 knots.

I cruise very nicely on the plane 14 knots, 3400 RPM.

I have posted more performance data at:

http://carlten.tripod.com/Performance/performance.html