305 Block

[bkhdmh]

I recently purchased a 89 Barreta with a V8 Volvo Penta, GM 305. I was told it had blown head gaskets but instead I found out today It has a cracked block. From the looks my friend says from not winterizing it. Can I use a 305 block from an automobile to replace mine? I plan on re-using my heads and internals. This is a "learner" boat and plan on trading it in for something nicer once I learn how to control this one. I would rather learn on a $900 boat than a $15,000 one. The local junkyard said if I pull my own block from one of their cars then the block is $105. I have also found a 305 block about an hour and a half away for $120. I would much rather drive the hour or 2 to get a complete running 305 for $120 than gamble with the other. I am going all the work myself with a mechanics help...no labor charges...and would really like to not have to throw too much money into this boat.

Thanks

 

[ajfetterman]

Re: 305 Block

I just replaced my 305 with a camaro 305 and it dropped in perfectly. I did reuse many parts from the old motor, mine too was cracked. The intake was different on mine and the flywheel. But other then that it went pretty smooth outside of my wiring problems. I marked some but not all....I recommend marking all!!

 

[dr_bowtie]

Re: 305 Block

too bad you werent close to me I would offer up a 305 just to get it out of my shop...

 

[jtybt]

Re: 305 Block

...and I junked out two 350 and one 400 block just to make room for another 400. That leaves me with a 350 on a stand, a 406 prepped and ready to drop in my present rotating assembly if I should need it and a 400 I'm letting sit till I get feeling to tear it down. Then there's a .040 over 400 I have laying around for the van. I need a bigger shop.

 

[bkhdmh]

Re: 305 Block

Well I got a 305 but got a older model from an 83. Didn't know the year of the engine when I purchased it. Turns out everything but the crank and oil pan moved over. But now the flywheel from my 89 doesn't fit the 83. The 83 was a automatic so it has the flexible flywheel. I am uncertain if I should by a manual flywheel for a 83 or just break down the engine and get an older model block. Is there a large difference in a marine flywheel and a automobile flywheel.

 

[bruceb58]

Re: 305 Block

You want something 87 or newer with the one piece rear seal

 

[Bifflefan]

Re: 305 Block

I am uncertain if I should by a manual flywheel for a 83 or just break down the engine and get an older model block. Is there a large difference in a marine flywheel and a automobile flywheel.

the old one should do fine. it should fit.
Its not like my motors that are fords. almost nothing fits from one to the other.

 

[180shabah]

Re: 305 Block

Really need to find an engine of the same vintage as your original (87-95). As you found out, you can't use your flywheel on the older engine, so yes you can get a flywheel for that engine, but now your existing coupler won't mate up, so plan on another $400 for that. Sell what you have and start fresh with the right vintage.

 

[Bifflefan]

Re: 305 Block

well there you go. I learned something too.
I thought a chevy was a chevy,

 

[fabrimacator21]

Re: 305 Block

Do yourself a favor and drop a 350 Chevy in it. They don't cost anymore and all the parts on the 305 can be moved to the 350.

Three things to consider:

Stay with a like year.

You need a truck engine to get the same type of low end torgue needed in a boat. (Cam and heads.)

You will have to marinize the new engine by replacing the freeze plugs with brass ones and install a set of marine head gaskets. (Can't have steel in them.)

Beware of the 350 swap.... I know a guy that went from a 200hp 305 to a 260hp 350 and he's kicking himself for it because of fuel consumption. If you have a big enough tank I wouldn't worry about it but the 350's do suck more gas.

 

[Bondo]

Re: 305 Block

If you have a big enough tank I wouldn't worry about it but the 350's do suck more gas.

?????????????????

Fuel usage is Directly related to the righthand of the Operator....

Hour per hour usage of a 350 doesn't burn anymore fuel than a 305.....

 

[futz]

Re: 305 Block

The guy who moved up to a 350 have a 4 barrel on the 350. If he doesn't get on it all the time so the secondary doesn't open up he won't burn more fuel.

Everyone wants more power, well it comes with a price, more fuel burning.

Me i use the boat for fishing 20-25 is fast enough for me. Only time i go wot, is about a mile away from the ramp on the way home, just to make sure the rpms are where thy are supposed to be, and if something goes it goes where i can almost swim to the dock.

 

[180shabah]

Re: 305 Block

YUP - fuel consumption is directly related to speed, weight and hull design. cubic inches and prop design, while they do matter do not make much difference at all.

If it takes 100 hp to propell a given boat at 30mph, it doesn't matter if the 100hp is coming from a 4cyl at 3600rpm, an v6 at 3000rpm or a v8 at 2500rpm. It is still 100hp and will consume somewhere in the neighborhood of 10 gal/hr.

 

[fabrimacator21]

Re: 305 Block

?????????????????

Fuel usage is Directly related to the righthand of the Operator....

Hour per hour usage of a 350 doesn't burn anymore fuel than a 305.....

Those statements controdict themselves.....


If your going to a bigger motor with more power but never use that power whats the point?

If you think WOT runs with a 305 suck fuel then a 350 is gonna be a rude awakening.

 

[dr_bowtie]

Re: 305 Block

BSFC between a 305 and 350 with the same hardware isnt that much different for a noticable amount...

even a 400 in good tune wont use much more gas than a 305 and in fact with the right cam and compression ratio can get better mileage than a 305...either can...

I just wouldnt use a 305 when there are other "free" options

free mean cubic inches...

 

[fabrimacator21]

Re: 305 Block

Well... I could be wrong... that was just what he told me.

But the going from a 2bbl 200hp 305 to a 4bbl 260hp 350 sure seems like the 350 is gonna suck quite a bit more. I don't know the cfm ratings on those carbs... but I'd imagine theres a 100-200cfm difference between them.

Bigger carb=more fuel consumption (atleast once the secondaries open up).

 

[dan t.]

Re: 305 Block

a larger motor running at 1/2 throttle will generaly use less fuel than a smaller motor running at 3/4 throttle, it is not working as hard, vacume is higher.this has been my experiance both with boats and automotive use

 

[bruceb58]

Re: 305 Block

If you drive both boats identically meaning that you accelerate at the same rate, drive a constant speed, they are going to have similar fuel consuption. The only difference is that with the 350, you will have some reserve that you can use if you need it.

 

[wca_tim]

Re: 305 Block

If you drive both boats identically meaning that you accelerate at the same rate, drive a constant speed, they are going to have similar fuel consuption. The only difference is that with the 350, you will have some reserve that you can use if you need it.

Unless you overcarb it and jet it a little rich too.

 

[WELLCRAFT707]

Re: 305 Block

Do yourself a favor and drop a 350 Chevy in it. They don't cost anymore and all the parts on the 305 can be moved to the 350.

Three things to consider:

Stay with a like year.

You need a truck engine to get the same type of low end torgue needed in a boat. (Cam and heads.)

You will have to marinize the new engine by replacing the freeze plugs with brass ones and install a set of marine head gaskets. (Can't have steel in them.)

DONT FORGET THEM 305 PISTONS WILL NOT GO IN A 350 BLOCK