adding 174 blower
 

I have a stroked 454 (489) in my boat, thinking of adding a 174 mini blower. boat runs low 70's now at 5200 rpm. Im thinking 4-5 psi boost. would this blower be worth the work, I would hate to only gain 2-3 mph.

What are you making for power? That blower simply won't move enough air efficiently to make over 580-600 and not be the equivalent of a pulled grenade pin.

what kind of boat? what prop? i would recommend first putting a -2 or -3 imco lower unit on your bravo first you would be surprised what that can do.
you did leave some info out what is the compression of the current motor what horsepower etc.?
year make of boat, how long how heavy?

boat is a 1993 obsession vortex 25, weighs around 4500. not sure on power guessing 500 horse, it is 8.5 to 1 comp. it does have a standard length bravo on it.

When B&M blowers first came out (many many moons ago), I used the 144 on a SBC and a 177 on a BBC in boats. They have to spin so fast to make decent boost and stay on boost for a long time in a boat, without a cooler, they make for a rather hot fuel charge. If the carbs are not set up and jetted right (or fat, always remember, "Fat motors live") mine always tended to lean out on the big end after running awhile. I burned several pistons (like acetylene burned) before I got it all setup correctly. There's alot of info out there now about the proper set up that wasn't around back then, so I don't think they're as tweaky as they were back then. Never got to dyno with the blowers, but did net about 6-10 mph out of a 20' walk-thru and 24' low deck v-hull.

yeah, I would hate to burn up a piston, I would probably start off very rich and go from there. I have heard of guys putting snow kits on the small blowers to keep them cool.

Skip the 174 blower on a 489ci engine. I'd go MINIMUM 250 blower, and go with the twin carb setup, over the single carb setup.

[QUOTE=bigbird241;4177444]boat is a 1993 obsession vortex 25, weighs around 4500. not sure on power guessing 500 horse, it is 8.5 to 1 comp. it does have a standard length bravo on it.[/QUOTE

how far below the bottom of the hull is the prop shaft now? i have seen so many boats handle and run so much better by putting on a -2 inch imco that if you find one used or by a shorter case and put your bravo guts in it.
it will cost less money to put a shorty on and also changes the boats running characteristics for the better. the boat will fly straighter if you hit a large wake. you will have to put a larger prop on which will allow 4 better cruise and top end. don't get me wrong, i love blowers but i would try and the most out of the hull and drive. then play with horsepower. a 256 blower with 2 carbs linkages etc. can be as much as $5000.
do you know if you have cast pistons, rods and crank if so i would not put a blower cast internals

[QUOTE=hullofjustis;4177957]my X is pretty high now, prop shaft is about 6 inches under center of boat. motor is built with forged pistons, h beam rods, steel crank. Im only looking for 3-5 psi boost, i dont want to invest in a new drive right now.

Sounds like you're good for 3-5 psi. I am starting an experiment with Prochargers on my Resto-mod Scarab. 5 psi max. These have intercoolers, so I will see. It might be an option for you too. Used setups are fairly reasonable.