Decisions Decisions!

[Professor GT]

Okay, so I'm new to all this sort of thing.
Actually back in the mid 80's I has an 18' Checkmate with a Black Max 175. It was fun. I bought it with the engine in a box, and rebuilt the whole mess. I learned to ski behind it and had a blast.
Now I'm a lot older and I just picked up a 1986 19' Sea Ray Pachanga with a blown up 4.3L Mercruiser/Alpha. My question is this: I want the boat for general enjoyment and to teach my young kids to ski. From what I understand, the 4.3 is good enough power wise to have lots of fun skiing. Since the water pump failed and the motor was over heated and now knocks, should I just refurb the 4.3L or should I swap it over to a SBC V-8? Is this an easy swap, or is it too much of a headache for the cost and amount of work involved. Will it consume a lot more fuel or will the boost in power even things out?
Sorry to sound like such a neophyte. I've build many an automotive engine, but I'm just not too familiar with the marine side of things.
Thanks!

[SmokinLowriderSS]

A small chevy V-8 will bolt in on the same mounts as I understand, COULD need some more room in front of it tho for the extra 2 cylinders, measure carefully before jumping. Just depends how close to the pulleys your engine area is. I suspect it'll fit as the SBC was likely a factory option.
Yea, it'll burn more gas, but shouldn't a LOT more,and I would go to a 350, no smaller, just to make the step worthwhile. Be ready to have to spend time re-tuning props too. The V-8 will be able to use a lot more prop than the 4.3L. If you plan on skiing 2 at a time (let alone 3), go V-8 IMO.
Also you will likely need to think about expanding the air inlet to the engine comartment, to insure the V-8 gets enough air to breathe. I have seen some pretty cranped bays arround the 4.3's... and I have seen some run better with the cover open than shut (that's pretty damn restrictive to me).
The cost'll likely be more as you will be replacing the entire ignition and fuel metering systems. IF the 4.3 was not FI, ther are a LOT of current comon occurences of hot-run-on with them that I have seen the last few years, on many boards. IMO they are pushing the V-6 just a good deal harder than they should, and it is showing up in vapor-locking, hard hot starting, hot idle stalling, etc that I have seen folks have trouble with. Thus, you may, once it is figured out, have less annoyances and agrivations from the V-8.

[Ryan00TJ]

Also remember the Alpha on your boat has the correct gear ratio for the 4.3L. Adding a 350 will likely result in problems as the gear ratio is too low for the 350's powerband. Most Alpha's beind V8's have the 1.47-1.50 ratio.
SmokinSS also raised some valid points.

[SmokinLowriderSS]

Also remember the Alpha on your boat has the correct gear ratio for the 4.3L. Adding a 350 will likely result in problems as the gear ratio is too low for the 350's powerband. Most Alpha's beind V8's have the 1.47-1.50 ratio.
SmokinSS also raised some valid points.
I keep forgetting they have different gear ratios in I/O's depending on the engine installed against it. Good thing I wheel a jet, I can remember it's 1:1. :idea:
Thx for the add-on Ryan.

[River Rat 005]

Don't forget the exhaust. You'll need different manifords.

[curtis73]

I learned to ski behind a 19' cobalt with the 3.0 four-cylinder and I weigh 230 lbs So many engines will accomplish the goal.
Any will be adequate in a 19' to take you from point A to B, but I agree... if you have the room for the two extra cylinders a small block chevy is literally a 4.3 with two more holes. (actually, the 4.3 is a small block with two fewer holes). So, in that respect a small block should swap in with no physical changes. water pumps, motor mounts, fuel pumps, bellhousing mounts, flywheels, couplers, etc, should all bolt right up. You'll need new manifolds and possibly need to extend your cowl a bit.
If you want to replace the 4.3 it will be a straight-on deal. If you're up to the small challenge, a small block 350 will probably cost the same, and get you more smiles.
I guess what I'm saying is: for the same money and more of your own research you could upgrade to the 5.7, but the 4.3 is adequate for what you want.