dockrocker

I kind of figure 600 hp is a fairly reasonable number. Not mega-bucks and mega-maintenance, and Bravos stand half a chance living behind it. Unless I hit the lottery, I don't see me having much more than 600 hp anytime soon...

Crazyhorse

Dockrocker, there were several Merc 454 packages offered over the years; 330, 365, 370, 400, 400 Cyclone, 420, and I've probably left out a couple. I'm not sure if the 440 was a 454-based engine. There was also a Bulldog way back when but I think it was a 540.
All but the 330 (310 in some ratings) had forged pistons , forged cranks, big rod bolts, four-bolt mains (MK IV), rectangle-port heads and aluminum intakes. Everything below the 420 had Quadrajet carbs.
If you're going to buy one of the older boats like the 311 you might consider limiting the horsepower to 500 or a bit more due to the transmission and TRS outdrive horsepower limitations. They seem to stand up quite well at 500 hp.

IRONMAN

The 440 was a 454 but did'nt really perform well compared to the 420. The cam was a little big and it gave up some torque. The 400 cyclone and 420 or 425's were very similar except for thr exhaust (400 Cyclones had the cast iron).

cooltoys61

SOOOOOOO Back to the orig question and away from the Merc history.
I have a couple of spare 454 mags,carbed and would like to know how to get to 550HP or so without reversion with Revolution Marine(Gil copies)exhaust. Can this be done with stock heads by just raising the compression to 9.5 and putting a cam of say 228/238,, 550 lift ,, the good bottom end should take 5800RPM for as long as you want to buy gas. How much more would it help to use a solid lift cam? I'm talking flat tappet here as I don't want to pay for the conversion I'd rather invest in a big cube roller block to begin with than do that.What about 1.8 rockers? Seems like a great way to cheat the cam into thinking it's a roller. How much does a hyd hurt? Should I start another thread for this part? Thanks

wannabe

Docker:

Posting to this thread, to refresh some older 454's w/o going to crazy should be about $2500 apiece and get you realistically 525-550 HP. This is very doable and will work w/o taxing the TRS drives and get you 3-5 mph. You really will need to do this anyway cause your daughter will push the throttles to the stops if she's a chip off the old block.

Wannabe

IndianaHeat

the Blower Ideal is more expensive but you can save the carbs and intake and put them back on if you sell the boat in the future, and put the blowers on the new boat.