Repower specs of my Bayliner 2955

I have just repowered my Bayliner, she was powered by 2X 5.0 Chevy OMC Cobra (230hp)<br /><br />Cruise speed before was 22 and top speed was 32<br /><br />I have replaced the old engines with 2 new 350 Chevy fitted with Performance Marine cams, Vortec heads, Holley 600, & HEI Dissy's.<br /><br />Each motor is rated @ 330hp and 380 ft lbs of torque @ 3800rpm<br /><br />I rebuilt the upper units and also installed the V6 Gear Sets giving the outdrive a ratio of app. 1.64:1, I did this to slow down the operating speed of the lower unit and this also allowed me to increase prop Diameter and Pitch. Propellers are Mercury Revolution 4 21P (4blade stainless Steel)<br /><br />The 1989 Bayliner 2955 avanti now cruises at 31MPH (GPS)@ 3000RPM consuming 15.8GPH (7.9 per engine)(FLOSCAN)<br /><br />@ WOT she runs 48MPH @ 4400RPM @ 46GPH<br /><br />What do you think<br />;-)

Re: Repower specs of my Bayliner 2955

Hello cam, and welcome to iboats, <br /><br />Sounds like a healthy increase in speed and 48 mph is flying in a 28’ Bayliner even with 650+ hp on board, but I’m not convinced you are getting the full potential you have with the engines if you’re only pulling 4400 rpm at WOT. You mentioned peak torque at 3800 is this where the peak HP came in also?? At their state of tune I would have thought you would need 4800 - 5200 to see the hp that your engines are rated at. (Unless your torque falls away dramatically after 4000). <br /><br />You have a nice pair of high performance engines and they sure are sweet! But are they working like truck engines? Held back by too much prop perhaps!<br /><br />What sort of numbers were you hoping to see with the re-power? <br />What fuel are you using?<br />Is your engine builder happy with the result?<br /><br />At the end of the day if your happy than life’s great, enjoy your boat.<br /><br />Cheers

Re: Repower specs of my Bayliner 2955

When I first read your post I thought Hummm, not to bad for the Ole Gal. I got to thinking about it later and would have to agree with Paulie0735. I run a 29ft Chaparral (see avatar) with a pair of Volvo Pinta 5.0Gi's, 250hp, turning 19 pitch factory props at 5000rpm. Tops out at 51/52 every time it hits the water, and have seen it run 54.9 gps once and an occassional 53/54mph. Load doesnt seem to effect top speed much either, 1 mph, 2 when really heavy.