Can anyone tell me if I were to have one of the best in the industry, Precision Marine ( Mark ) re flash my ECM, on my stock 496 mag, what could I expect to gain? I am 4640 @ WOT with 4 people and 3/4 tank of fuel. Would I be giving up any reliability and economy? I know it is expensive, but is it worth the gains if any?
Thanks in advance.
Gary

unless you upgrade the cam to a HO I would think not much if anything at all...

By the way Dustin from Whipple is the only one authorized to program 555 ecus..

First off I would get some prop work done to get your RPM's up to 4,800 at WOT. Then I would leave it alone and enjoy.

+1

Get a Dustin Whipple Stage 1 or 2 and spend the rest on prop work and a 496HO cam. A custom ecu tuning is not cheap in any way.

You need an ho cam and ecu reflashed By dustin he is the only one in the country that can do it your rev limiter would be 5400 and you should gain 1 mph per 1000 rpm,s It should cost about 1000.00 for reflash and cam,plus labor for cam install

Get the prop maximized first.

Then call Mark at Precision and ASK HIM exactly what he can do on a flash and what you MIGHT expect to see in gains.

Change your exhaust.

That seems to be the biggest bang for buck on the 496 from the articles I have read

Last I talked to Mark he was NOT able to do a 555 ecu..he had to send it out to someone he deals with..

But I would not waste my time with just the ecu reprogram..

This is what you need to do,,,Cam,,Drill idle bleed hole on throttle body from 1/8 to 1/4,,,ecu reprogram..prop...New engine cover decals...
I have done it on my last 2 boats and worth it!!

+1

Use Raylars cam. By the time you find a HO cam and spend the money you could have the Raylar cam it is slightly better than the HO cam. Do the ECU, prop and thats all you can do to keep the reliability. For what its worth, replace the springs and add Raylars full roller rockers while you are in there.