Heck, all this time I thought it was alcohol and testosterone.

A 600 inch motor is gonna make torque no matter what you do to it.

Timing below 28 degrees will just make the exhaust valves run too hot. But it should soften it up a bit.

A throttle stop will limit your top end hp/torque, but you'll still make huge torque at low revs (which is where you'll most likely kill the drives, coming onto plane too hard or accelerating from a slow plane).

You can probably get some custom rockers made at 1.5:1. Will reduce your valve lift by 12%. (from .600 down to .530)? On second thought, that won't kill enough torque down low either, mostly up high.

Take out a couple of pistons?

Reduce the pitch of the propeller by 4 inches. That will take the load off the drive at all rpms. Just don't overrev the engine at the top end.

Patriyacht has best idea!

Patriyacht ... What a great idea. Why didn't I think of that? I can drop 3 pitch and still hit 78- 80 mph!!!! I'll get to enjoy the boat till mid-summer when I can do the drive upgrades. THANKS!

ya... dont over rev ...break a spring ...float a valve .....boom! 4 inches ? alot ?

redline shockproof heavy in drives. i am a firm believer. blown 540,s 10.000 lb boat 30 inch bravo ones. nrever blown a drive. you will need a bigger resovior as it does tend to expand more than mercury hipo gear lube.

I agree with the Redline gear lube and run drive showers. So far I'm having good luck with my overloaded Bravos but my boat never flies and I baby it onto plane.

I'm installing the crane brain boxes to have an adjustable rpm limit. That should do the trick.

try pulling 1 plug wire off each engine or buy some ssm#3a's i think tommy at chief has 2 complete setups for 10 k he may even take a bit less and sell your drives to offset the cost. then USE that big torque...