290 Prop Selection question again
 

dyno'd first engine and hp looks like 480 with torque at 525. because the dyno is an antique i dont have answers to the many questions you may have however the guy said the peak hp was reached around 5-5500rpm. my plan was to prop for 5000rpm at wot. i have 24" bravo 1's now (ran 60 gps @ 4400 with 7.4's) and feel that i should be able to run 26". i have bravo 1 drives at 1.5 ratio. any thoughts based on this info?

Did you trim it or was that with the drives all the way in?

start with the 24's

hey BBYSTWY i was trimmed out no tabs in the water probably pretty full of fuel and had a friend with me. liberator221 i will keep the 24's but I'm really wondering if this extra 300 hp will allow me to run 26" props and increase my cruise to 60 ish @ 3500 and move my wot speed to the low 70's at 5000.

You will never run 60mph at 3500rpm with a 26. My boat ran around 48 at 3500 running a bravo 1 prop with decent slip numbers.

Run the 24 and see how it does before you start buying props.

Run the 24's for a base line. If you were only pulling 4400 RPM prior you will probably be in your 5000-5200 now.
If you feel you need 26's I have a set you can try before you go prop poor.

No way to really give any really good advice without some real dyno numbers or at least the engine specs

i was bummed that i couldn't get a dyno print out. anyway, i kept the stock bore and stroke, upgraded connecting rods, hypereutectic small dome pistons. supposed to be about 9.8:1 compression. roller cam 230/236 @.050 and .547 lift, went with afr aluminum 265cc heads 112 combustion chamber, stainless roller rockers, Edelbrock rpm air gap intake and quick fuel 800cfm dbl pumper. it ran easily to 6000 rpm. seems to be a nice combo and again hoping to run in the low to mid 70's

Is it the 7.4 with 2 bolt mains and cast crankshaft??

My old dock neighbor had a similar build in a Formula 302 that ran mid to high 70s. He also started with 7.4s. I believe he had many relatively trouble free seasons with the boat and it sounded great.