I'm having the same issue on my Baja 272. Fresh 500+ horsepower, tried different props, but still running 23% slip @ 54mph in a boat that does over 60 with the stock 454. I'll be following this saga closely.

Cole, my buddy Tim was running over 80 MPH with essentially the same hull / drive depth combo. But maybe it's just something about my boat. Checked hull for straightness in the past, and actually had factory "hooks" removed several years ago.

motor, engine was dyno'ed by Dale Meers Racing Engines near Hodgenville, KY. Stuska dyno running Performance Trends DataMite data acquisition software. He does primarily drag, circle track and truck pull stuff, but has a pretty good reputation around these parts, especially for the MOPAR guys.

This run was on the Ohio River, north of Westport KY.

Did you dyno yours before running it in the boat?

I'm going to give the engine a good looking over, basic health check. Only has about 20 hours on it. Wish there was a way to run an O2 wideband with these lightning headers, but as others can attest, they love to kill sensors.

Budman II, Sorry to hear about your performance after all the hard work.
I would think it should go faster also. The slip factor doesn't seem that terrible, mine runs at 17-18% slip, but it's a bigger boat. A stock 502 should get you to 60mph, so it seems that you are loosing power somewhere. I would definitely start with the easy stuff first, like timing and throttle. Also a dead cylinder/broken spark plug etc. could cause the issue and you probably wouldn't hear it. Try it again after you get most of the weight out of the front. I can take 10 mph off mine with extra weight in the bow. Something seems to be holding it back. I know it isn't a real fast hull, but at 60 your not asking that much out of it.

I think you have to much prop. We put a 496 in an '89 Baja 240 and it runs 72 with a 23" 3 blade or a 22" Bravo1 and 1.5 gears.

Too bad you weren't close by. I would love to become involved with your puzzling man against machine war. My problem is I don't give up early enough. LOL.

heh, first I would do , if not already, is check with other 'same exact boat' owners and see what prop works best. I'm not necessarily talking just pitch here.


I think a Prop dyno would be great here. Find out if there is some tuning or rigging issues going on.

Example: My insert mufflers cost me a little over 2mph.

Example #2: My 9x4 K&N flame arrestor costs me a little over 2mph. My big bad testing assault day it was closer to 3mph.

Disclaimer: Remember, my current little (20ft) sbc boat responds + and - mph wise to anything and everything. I swear I can change mph by turning my hat the oppsoite direction. LOL.

Also, to answer the original question, I have always got the least prop slip at top speed with slip increasing down though the midrange.

The sensor itself is an $80 part mass produced by Bosch for Volkswagen originally.

Prop Dyno would be ideal. Trying a smaller pitch is worth a shot too. You're propped to run up to 80+ at 6000rpm.