what do you think about this problem 1996 26 cloe boat weight 4900 lbs with the 454mag 385 with a performance yune that requires 89 octaine leak down was done be fore install and all was ok per GT performance.
So I went for my sea worthy test today and everything accept the top end was as good as my genesis 236. However max RPM 4500 to 4600 and speed was 54 to 55 with a 21 3 blade.
Is the boat just to heavey for my motor application as is and the exhaust along with a prop change by the formula of boat speed taht would get me to 4800-5000 per the formula Or maybe I have a motor down on power it is a 365 hp with carburator I had them retrofit a F/I for the 385 hp mag and a performance tune was done on it. The #'s above reguarding speed and RPM 4500 4600 @55MPH is a 10% slip factor witch is a great # for a boat built in 96
*******would you raise the drive an inch I have done this before and it gave me 200 more RPM's. Theway it was explained to me we will put on a 23 wich will loose 200rpm not sure that change is a good one and the other deal that was talked about is some Imco exhaust toraise the rpm 300 rpm's and one up or more prop size depending what the exhaust do what is your tak on this situation. The boat is to heavey to run a single 454 385 hp in the mid 60 to 70 mph???????????????????????????????????????
BTW I did not do my homework on the engine that was beeing put in. It's a 454 mag carburated 365 hp I thought that if i had them add the F/I to the motor that would compencate for the additional 20hp of the 454 385 hp F/I.
Well as you know that is not gonna do it. I was told that the 365 hp version has a flat tappet cam and the 385 HP versin has a hydraulic roller for the extra 20 hp. Do you think that putting on an after market flame arrester and a performance tune symilar to what arizona speed does will that get me back into the 385 hp range? they are re tunning the original to have more timing and fuel and I will have to run 89 octain witch is fine with me. Also is it safe to say I can pick up 200 to 400 rpm with imco aftermarket exhaust
If the water was not like glass we should have picked up 200 rpm's is that statement true also. I think it is with my other boats it did exzactly that just want to confirm with you since you test out there all the time in the GREEN MONSTER LOL