Prop selection help for a Mercruiser 330 / TRS
03-07-2017, 08:40 PM
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Prop selection help for a Mercruiser 330 / TRS
I need some help with prop selection. I’ve was handed down a relative’s boat back in 2014, spent most of 2015 doing some refab and rebuilding the motor. Got it back in the water in early 2016 and was content with just having fun, cruising, and pulling tubes. Now it’s 2017 and I’m looking for speed. My setup is a Dave Stoller Custom Deep V Boat from 1983. It has a Mercruiser 330 / Borg Warner 1 to 1 with a TRS in good condition. When my Uncle had it made it was delivered with a 2 bladed racing prop and would run 58 mph turning 5700-5800 rpms off speedo and tach (same one’s still installed in the boat). Over the 31 years he’s owned it props would come and go, and he doesn’t recall what he’s used in the past. When I got it in 2014 it came with a Mirage Plus 19P and again I was content to just roll with that. The bad, at WOT it turns over 5700 and climbing with only 51-52 mph to show for it, I don’t let max out due to the high revs.
The motor, Mercruiser 330 (454) bored .060 with the standard stock Barr Marine exhaust, 1972 Chevelle heads (can’t recall the casting #) 202 -181 valves , Torker 2 intake with a Holley 750 4160, Crane 134242 hyd cam with roller rockers, Thunderbolt 4 and it makes 60 psi oil at idle with a stock pump/ pan.
The boat’s 25 ft deep V with cuddy cabin that only a toddler could fit in, weighs over 3200lbs ( guessing), and has power trim with working Bennett Trim Tabs. Any adjustment with the tabs, or outdrive position while trying to get more hull out of the water only slows me down.
Props (all specs off gps, one person with 20 gals of fuel – holds 60 gals), it came to me with the Mirage Plus 19 (no damage) , cruising speed is 39 mph @ 4950, vac sec come in and I’m 51-52 mph over 5700.
Purchased a used Mirage Plus 23P ( no damage), cruising speed of 37 mph @ 4900, WOT 49mph @ 5600. Same weight , same day, no wind-smooth lake.
Purchased an Amita 3 23P for Christmas ( that’s what started this whole ordeal) trying to get my rpms down, Took it out in January , don’t recall the cruise specs but at WOT I was at 5000 rpms running 50mph. Not too bad, took the family out the next weekend, and it was slipping at WOT was 5500-5600 for only 49-50mph.
Did some research and found out too late the Mirage’s are known for slipping. I know this boat is heavy , but my rpms should be under 5000 at WOT. Any suggestions. I’m not sure where to go from here.
