350 Engine advice--GOOD UPDATE!

[MikDee]

Re: 350 Engine advice--GOOD UPDATE!

Ok, you don't say what size prop you have, if it was an orig. 230hp/305 it's probably a 19" pitch, and the rec. rpm range for that engine is 4400-4600rpm, and a 50mph boat as it was, considering I had an older 228hp/305 in (probably) a heavier 20' SeaRay bowrider that would do 50 with a 19" pitch prop, I'd say it's not the heads holding you back! There's something else going on!, that boat should do 55 easy with a 355. I suggest you go over that engine real good, it's got the guts to do more then that, even with a "plain vanilla" stock cam.

I told you that boat should do 55 easy with the 355!
And that's GPS! Plus you're running out of prop now. There's more to be had there, I bet with a light load, and some synthetic oil you'd get to 60!
Do ya really think you need a cam, & better heads?! Whatever, Good Luck, Mike

 

[QC]

Re: 350 Engine advice--GOOD UPDATE!

It ran 54mph on GPS with 3 people and 1/2 tank of fuel at ~4800rpm.

Personally I would not assume your are under wheeled right now. IF the tach is correct and IF your load is typical, then you may be just right . . . She would swing another two inches with a light load, but almost all 50+ MPH boats should jump on plane. 54 MPH means you got some decent power there, light boat etc. Also, while a stock, carbed 350 is typically rated between 4200 and 4600 RPM for WOT you don't have a stock 350. Who knows where her power peak is? Not me . . . I would wait until you play with the cam as you have noted (was that already done?) then think about prop changes after you get performance numbers from that setup.

 

[n2ostroker]

Re: 350 Engine advice--GOOD UPDATE!

Personally I would not assume your are under wheeled right now. IF the tach is correct and IF your load is typical, then you may be just right . . . She would swing another two inches with a light load, but almost all 50+ MPH boats should jump on plane. 54 MPH means you got some decent power there, light boat etc. Also, while a stock, carbed 350 is typically rated between 4200 and 4600 RPM for WOT you don't have a stock 350. Who knows where her power peak is? Not me . . . I would wait until you play with the cam as you have noted (was that already done?) then think about prop changes after you get performance numbers from that setup.

Sorry I reread and my last post was a little jumbled.

Those are plans for the winter time hence the wanting to try a few different props come spring. I have no doubt it would pull out of the hole repropped, Just don't know about the gain up top as it is now. The motor as it ran is a box stock 355 with the 305 heads and cast iron intake. The carb is jetted the same as a Mag 350 motor. The peak power is definitely at a lower rpm. She starts to run out of steam around 43-4400rpm. You can just feel it. I have no idea what cam is in the motor. It was out of the 305 and the lobes and lifters looked brand new so I'm pretty sure it had been replaced with some kind of automotive camshaft. For how the boat performs as it sits I'm really happy. At least I got to use it a few times before it's time to park it for the winter.