Storm-
You could probably get the flippers from the 280 tabs and bolt them up.... I think the transom mounts are the same..
A lot of guys change the flippers from 280s to 380s....

Albert may have some 280 flippers you may be able to get hold of....

Tim, thanks, but Jo says the short tabs will work better, as the boat not being as sensitive to them... I can always change if I feel differently.

Jo/Pepe, you can chime in on the slip issue anytime.

River rat dude,
I was reading your post felt I would chime in ( for what its worth) .
The cam you are running is a bit aggressive. 240 @ .050 is a bit radical. Is it a roller , or flat tappet?? I think it will work fine however , if you get rid of the exhaust manifolds you have . That cam in a 10:1 454 should make over 500 hp in the 5600-5800 RPM range . With the high duration comes overlap, and overlap in a motor requires good exhaust to help scavenge.
Throw a set of CMI elbow tops on and I am sure you wont be able to hold on anymore .
Remember , hp isn't everything - Torque is king -When in doubt , less cam is better .

Good Luck !

You make a good point with the exhaust.

I'm considering changing to headers from my Powerflow manifold. Might help the engine breath and pick up a few HP.

Pan 28,
I was running a set of Gils in my 540 , which had a cam in the 240/250 dur2 .050 range, with 114 LS .
When I changed over to the CMI elbow tops , I picked up 6 mph and 400 RPM . A night and day difference .
From my experience , cams with Intake less than 220 @ .050 and with little overlap ( 114 or higher) will work OK with stock exhaust . Little gains would come from CMI , or good flowing exhaust in these engines .

I'm running a Crane HR-214/325

[email protected] [email protected]
.059/104 Degree Intake
.034/114 Degree Exhaust
Gross Lift .553 with 1.7 Ratio Rockers

The only difference between the Dyno and the boat was the exhaust. I have still had a difficult - next to impossible time getting up over 5,000 RPM in both my 24' and the 28'.

Sorry, didn't mean to hijack the thread!!!

Kirk, I'd call IMCO.

Kirk,
the cam you are running has 214 @ .050 , andlooks to be installed on a 104 Intake Centerline .
If so , I am sure it will not turn over 5000 RPM in the boat .
I doubt headers will do much here . I am sure this cam makes good torque . It is pretty mild . You said you put this motor on a dyno?
What did it make and where ? What exhaust was used on the dyno?

How much boost do you see at 5000 Kirk? Is the carb at least an 1100 dominator?

The cam has been installed at 110 Degree Intake Centerline.

It's fuel injected with larger injectors, cleaned and flowed. ECM reprogammed in the boat while running helped a little, but still not getting the same power as on the dyno.

Dyno Numbers:

RPM HP Torque

4000 542 711
4500 603 705
4800 625 684
5000 626 659
5300 642 635

Thanks for the help!!