Replace 470 w 30

I have a 1978 galaxy runabout

I have a 1978 galaxy runabout with a 470 merc. and pre alpha outdrive.I would like to replace the 470 with a 3.0. Will a 3.0 be plug and play or will I need to change anything as far as the outdrive and engine coupler etc. Thanks Dale

"Some guys don't think you

"Some guys don't think you will need to change the gearing ratio but they are different. I would if I was doing the swap. 1.98:1 for the 3.0 and 1.84:1 for the MCM470. What year is the 3.0? If it came off a Gen II I'm not sure it will be a direct swap. The MR, pre-alpha and Gen I are all pretty much interchangeable."

"You will lose 35 HP. Are the

"You will lose 35 HP. Are the transom, floor and stringers dry and solid; no rot?"

"I haven't found the 3.0 y

"I haven't found the 3.0 yet still looking for a good used one, I'll be sure to look for one that is compatable with the gen. one. I'm not looking to set any speed records so the HP loss is not a big issue,it should still push the 18'er along nicely.The boat was supposedly stored inside in winter, every thing looks to be very soild. If I can find a good used 3.0 up to about 1988 or 1990 for a reasonable price it'll be better than spending 2000.00 or more to rebuild the 470."

and i would say that 2000 is b

and i would say that 2000 is being conservative

"Guy brings up a very good poi

"Guy brings up a very good point with the loss in hp.
I replaced a 120 hp with a 470 years back on a 19' Reinell and the performance difference was immense. The 120 had to run almost constantly at wot to give any kind of performance, whereas the 470 ran happily at 2800 to 3000 rpm to give equal performance. It also pulled up skiers easily, and gave me better fuel economy. It's totally fresh water cooled, and a real work horse. I ran the 470 (new) for over 30 years and it was flawless. You may be happier with a rebuild on yours, or finding a 4.3 (190 hp) rather than the 3.0 (about 135 hp)."