Re: Stingray Make Over
Cheapest fix: USED 4.3L V6 outta some random Chevy out of a junkyard. All you will actually use from that is the long block (block/rotating assembly and the heads). Every single other part you will re-use from your existing motor...manifolds, risers, bolt-on water pumps/alternators/ignition/carbs, etc. that are all marine rated and presumably already tuned and in good enough condition to run well on a 4.3L long block. All those marine parts will bolt right onto the Chevy truck longblock and work fine. Most junkyards provide at a minimum a 30 day warranty for parts only, so you can have some assurance that you didn't get a garbage motor or they'll exchange it for free, and yet other big name yards (who will charge more for the engine) often provide you with a 1 year warranty that covers parts AND labor.
You'll also get get a bonus HP bump of about 25 or 30 if you currently have a non-Vortec V6, and you find a chevy truck motor that is a Vortec V6. But then again you may run into problems with bolt patterns on the manifolds if you switch engine types...research this and don't take my word on it.
Now this "cheap" fix assumes your freeze damage didn't already crack your risers or manifolds. Even then, they will need to be replaced anyway, regardless of your engine source.
Just another direction to look, FYI. Most people only consider "mercruiser" new or remanufactured engines when this sort of thing happens. But chevy truck blocks are pretty much identical with only slightly different cam/valve timing. They work fine and are far cheaper and more easily available than true Mercruiser motors, as long as you bolt them all up with proper and safe marine rated parts...which you already own and have on your boat. I'm speaking primarily for freshwater boats. If you run in saltwater I have less knowledge...something else may need to be considered but I don't really think so.
Switching to a V-8 IMO would only be economical if you go the marine engine salvage route where you can gut EVERYTHING out of another boat. This is because when changing from 6 to 8 cylinders you will most definitely also need to replace your manifolds, risers, carb (maybe), distributor, ignition system, engine mounts, etc, etc, etc. The cost of all those parts can easily exceed the cost of the engine itself. Therefore your price will go up exponentially. Not sure the outdrive would need to be changed, I bet a prop with a steeper pitch would solve the gear-ratio differential problem quite adequately, and still keep you in your target RPM.
You don't say how old your boat is. You also don't say whether you are considering relacing this motor yourself or if you will have to pay labor. Assuming you will pay someone to fix it, and assuming it's 10 years old or so, you might seriously consider just buying a replacement boat and selling your current one as-is. If your boat is in otherwise good condition for its age, it could be worth more than you think. Very handy people will know how to do the first Chevy-junkyard swap I mention with their own labor for less than $1,000 in parts. So people like that they often LOOK for clean boats with blown motors so they can swap a motor themselves an flip it for profit, or keep it for themselves. I am one of those people, and that's exactly why and how I bought my current 20 foot Stingray for 50 cents on the dollar last fall...from a pawn shop that got burned on buying a boat with a cracked block!! I fixed it cheap, and it's an awesome boat I am just starting to now use frequently.
As for your other questions. Yes, tower on a 20 foot V6 makes sense, not uncommon. Perfectpass will help even more if you're getting pretty serious into wakeboarding. Ballast bags, etc will help quite a bit with making nice wakeboard wakes, but they won't help much with your planing speed. Gearing down with smaller pitch prop, increasing horsepower, and/or trim tabs or Smart tabs are the normal solutions to better planing speeds. All depends on how deep your pocketbook is and whether you think this boat is worth investing.
As for your prop question, nobody can answer this without knowing your current prop and current performance levels, WOT RPM, top speed, etc. Generically speaking, 4 blade props are better for watersports than 3 blade props, and shorter pitch props will plane and accellerate better if you don't get put into an over-rev situation. Your target is PROBABLY 4,800 rpms at max top speed, but again we'd need to know your year/make/model of engine to know for sure.
There are subforums here that will help you find more people who are more helpful for your situation. Mercruiser I/O sub-forum will help with your engine swap and replacement questions...most of the mechanics don't hang out here in the wakeboarding sub-forum. Prop sub-forum will help with your prop questions. And this wakeboarding sub-forum will help with your tower and ballast bag questions. Split your questions up among them if you want more help and wider variety of opinions.
