Bought an I/O VP Boat With No engine, so building new one

[Windy Bay]

I have purchased an older boat (1980) skipjack boat with a 290 out drive and basically no engine. It came with a block and heads, and most of the tin. I have the original carb, fuel pump, water pumps, alternator, fuel pump y pipe and other misc parts. I don't have flywheel, vibration dampner, main bearing caps, rods or rod caps. when looking up the engine identification, the block and heads are not the original parts, and I have determined that they are junk. So I am building a new engine for it. I am going to build a 383 stroker with good quench effect pistons with information I have found elsewhere. My questions are, what should I look for in a block and heads that will match up with the accessories ie alternator bracket raw water pump bracket ect. any help or information would be greatly appreciated. Oh and it originally had a 260b.

 

[o2batsea]

The cost to build this up from a bare block will be far more than just buying a crate motor from our host. What you will need to find is a donor engine so you can pilfer the intake manifold and brackets.
Honestly I'd tell you to find a boat that's in running condition. Nothing free (or cheap) ever turns out to be in the long run. I would hate to see you spend thousands on a boat that will be worth only a thousand bux, or worse, nobody wants at any price. Sooner or later you'll want to buy another boat, so pick your projects with an eye on resale value.
If you proceed, try to find a duoprop lower for the 290. That will greatly improve the value along with the "user experience"

 

[RicardoMarine]

I have purchased an older boat (1980) skipjack boat with a 290 out drive and basically no engine. It came with a block and heads, and most of the tin. I have the original carb, fuel pump, water pumps, alternator, fuel pump y pipe and other misc parts. I don't have flywheel, vibration dampner, main bearing caps, rods or rod caps. when looking up the engine identification, the block and heads are not the original parts, and I have determined that they are junk.
Unless you want to machine and line-bore a set of different main bearing caps, a bare block without them is useless!

So I am building a new engine for it.
1.... I am going to build a 383 stroker with good quench effect pistons with information I have found elsewhere.

2..... what should I look for in a block and heads

3..... that will match up with the accessories ie alternator bracket raw water pump bracket ect. any help or information would be greatly appreciated. Oh and it originally had a 260b.

1..... Keep in mind that the correct pistons will offer a quench surface, but also that the quench dimension becomes critical.
This involves a correct piston deck height and correct compressed head gasket thickness.
In other words, a quench style piston cannot perform unless the quench dimension is also correct.

2..... I'd go with a later cylinder block that is roller camshaft ready.
If you go with the GM Vortec cylinder heads, you'll also need the Vortec intake manifold.

Pistons cannot be selected until you have until you have decided upon cylinder heads, and likewise cylinder heads cannot be selected until you have decided upon a piston profile.

Take a look at this thread beginning at post #7.


3..... The 6.2L (std 4.000" bore/ 377 cu in) or 6.3L ( 4.030" bore/ 383 cu in) are built upon the 5.7L cylinder block.
The stroke for either goes from 3.480" to 3.750".
Minus the harmarnic balancer and flywheel, all previous 5.7L brackets and hardware should fit.

BTW, your AQ series drive requires the 153 tooth flywheel.
If you buy a stroker rotating assembly kit, purchase the 153 tooth flywheel with it.

The cost to build this up from a bare block will be far more than just buying a crate motor from our host.
Any crate engine will be fitted with the dreaded GM style full dished pistons.


Honestly I'd tell you to find a boat that's in running condition. Nothing free (or cheap) ever turns out to be in the long run. I would hate to see you spend thousands on a boat that will be worth only a thousand bux, or worse, nobody wants at any price. Sooner or later you'll want to buy another boat, so pick your projects with an eye on resale value.
If you proceed, try to find a duoprop lower for the 290. That will greatly improve the value along with the "user experience"
I do agree with you on this.
If he builds a good Q/E into this stroker engine, he'll want the 1.78:1 ratio.... not the 1.95:1.

Here's my take on boat ownership.

Quite frankly, boats are rarely investements, and are almost always expenses.
No rule states that these are investments nor that we must get a good finacial return on the day that we sell.
A good attitude to have is in understanding this.
If not... you should probaly not be a boat owner!!!!!


Take the total cost of your boat project... from purchase to restoration completion.
You will be satisfied in knowing what you have... and there is a value to that.
Take the number of outings, or years of usage (or use your own formula) and divide this into your total cost.
There is your cost per outing or per year of ownership.

Example:
$20K spent on purchase and restoration.
You enjoyed 10 years of relatively trouble free use.
Minus fuel, that's only $2K per year.

If you and your family enjoy boating, what else can you do as cheaply?


Plus.... who better will know your boat than YOU?


.

 

[o2batsea]

When building a marine engine, think in terms of an engine that will run a generator, not a dragster. You want to be able to run it for long periods (like hours and hours) at 3500 rpm. I would start looking at a diesel for that boat. Seems most Skipjack people repower that way rather than with gas. Marinizing a Ford truck Navistar is a pretty common happening and those can be had for cheap. You'll need the Osco manifold, a heat exchanger, and a seawater pump. That's about all there is to it. That's how they do it for work boats around here. That or the horrible GM 6.2.
I dunno where you are, but there's a guy here in Maryland who wants to give me a Wellcraft 29 with two chevys in it. One runs the other needs a head gasket. Free for the taking, but you have to take the whole boat.

 

[Windy Bay]

This is not my first rodeo. I have owned many boats, starting with a 63 glaspar, a 23' can't remember the brand, 18' Mark twain, all mercruiser, 32' steel trawler "diesel" 24' skipjack open, which is my first Volvo Penta with the DP which is the boat I am currently using, and now my 25' skipjack sport cruiser. The wife won't let me sell the 24' open until I get the 25 sport cruiser ocean ready. I found this boat in a barn, literally, and it has not been in the water for at least 20 years. I paid very little for it so I have a lot of room to improve it. I would love to go diesel, but I don't want to end up with something that I can't work on. I have rebuilt small block chevy's in the past, and have a good mechanical background. I'm thinking this might be my last boat. At 61 I want this boat to last for 15 years or so. But there is always the "a little bigger sure would be nice". I love to Tuna fish (albacore tuna) here off the Oregon coast. I also like salmon fish, and want to learn how to fish for halibut. For tuna and halibut the run off shore is anywhere from 15 to 40 miles, so I want something reliable and as economical as I can get. That is why I chose the Stroker. I have read some of Ricks post in the past, and some of his post on other forums. I don't know how the stroker will perform trolling for tuna (about 1200 to 1500 rpm) or trolling for salmon(as slow as I can get it to go) but the run in and out at 3000 to 3500 should be good on the stroker engine. Rick, thanks for the heads up on the flywheel, that was exactly the kind of information I was looking for.

 

[RicardoMarine]

When building a marine engine, think in terms of an engine that will run a generator, not a dragster. You want to be able to run it for long periods (like hours and hours) at 3500 rpm.

I fully agree...... and is all the more reason for a Q/E build.
A Q/E build will help avoid detonation potential, of which will generally prevent high cylinder temperatures, etc.
The main purpose is so that the ignition timing no longer needs to be lazy...... of which typically results in a much better LPCP..... of which results in more torque.

Rick, thanks for the heads up on the flywheel, that was exactly the kind of information I was looking for.

You are welcome.

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