gear ratio is 1.5 it has 300 hp boat is super heavy im running a 3 blade aluminum prop right now dont remember pitch off top of my head. it will turn 4500 rpm wide open all day long maybe its not proped right? goto a 4 blade?

If you build a motor big enough to go fast, the drive is going to scatter. A 425 HP 383 is going to run better than what you have, but still not fast. Your boat may start eating drives even with the 383, and a 4 blade would make it worse.

well ill prob just swap out the alpha to a bravo what would be a real world mph increase with a good built 383?

Aluminum prop flexes a lot and looses speed but 35-40 mph to me seems very low. Even if a stainless prop got you 45mph you'd need 550 hp just to break 60! Unless your current engine is hurt.

so i finaly checked speed with gps and boat runs at 45 mph turning 4600rpm thoughts on where to go now?

I agree 100% !

If your engine and tuning and prop is right on, I would not look to add 100hp as that won't do anything much.

300hp now at 45mph means you'll need a quazillion more hp to even think of getting into mid to upper 50's.

Before throwing $$$ at the present combo for now, I'd call Sleekcrafter and find out what your boat runs with a 330 7.4L and a 385hp 7.4L. This will answer the question if feasible to up the power or not.

300hp at 45mph. yikes !

NO MATTER WAHT....TOURGE IS TEH KEY..NOT HP ..so any BB IS BETTER THEN ANY SB !!!!

hope that helps

sb is the yikes a bad commen? its a big heavy boat not sure on weight but shes a big girl. was full of 60 gal of fuel 2 full ice chest and 3 people.

yikes = ouch

300hp for only 45mph.

Means you'd have to step up power a ton (okay, a schitload...lol) to gain another handful of mph.

Say if you had a lightweight 18-21ft boat with a good running bottom, the 300hp may be running 65 or so mph. If so, then an extra 100hp would mean you'd run alot more addt'l mph over the 300hp baseline. Starting at 45mph means that your boat doesn't want to run fast and will be a lot more resistant to running faster.

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Could you beg/borrow some of the more normal stainless steel props to see what it really can run as is ? Aluminum usually costs a bunch of speed.

If you could run say 50-55mph with boat as is, then adding more power would be more worth the results.

Sorry...sometimes hard for me to type my thoughts.