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350 with 302 heads?

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nsxxtreme

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I know there are some engine builders on here so I thought I would ask for some suggestions.

I have a boat with a volvo penta 302 V8 wich is basically a chevy 302 from what I understand. I'd like to get some more power in my boat so was thinking of sticking a 350 in the boat. I was thinking of picking up a 4 bolt main short block from the junk yard and rebuilding it. Would the 302 heads work on a 350? No real particular reason I want to use the the 302 heads just would be nice if everything bolted up. This project is at least a year out so I'm just looking for ideas right now.
 
1st im pretty sure that the volvo engines are ford based. Is the distributor in the front or back of the engine?

If it is a chevy based engine in there then you need to know what size the combustion chamber is on the heads so you can figure out your compression ratio. That will be one of the big issues to deal with. Also you need to look at what size the valves are to make sure you will get enough air flow you would hate to throw a bigger shirt block in to find out that the heads limit your power and you are right where you started
 
Chevrolet offered the 302 for about two years; 40 years ago!

The Chevy 302 was essentially a 350 block (4.00 inch bore) and a 283 crankshaft (3.00 inch stroke).

You may very likely have a Chevrolet 305 in your sterndrive, but it would be very, very doubtful it's a genuine 302.
 
Heads will work. Once you get it torn down you can figure out what piston you need. A marine gaskets set and maybe have marine shop pressure check heads
 
Wasatch K5 said:
Chevrolet offered the 302 for about two years; 40 years ago!

The Chevy 302 was essentially a 350 block (4.00 inch bore) and a 283 crankshaft (3.00 inch stroke).

You may very likely have a Chevrolet 305 in your sterndrive, but it would be very, very doubtful it's a genuine 302.
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Ya basically just a brain fart that day. I don't work on American cars often so I fumbled the numbers. I shoud have caught it since Chevy always has to out do Ford by a couple of CC's. The motor is a 2004 so it's definately not a 302 :D

I should have said a volvo penta 305 chevy motor. It produces 220 hp so it does ok, but I would like to be at about the 300HP range.
 
63chevyll said:
Heads will work. Once you get it torn down you can figure out what piston you need. A marine gaskets set and maybe have marine shop pressure check heads
Click to expand...

I didn't know there was such a thing as a "marine" gasket set what's the difference?
 
marine engine stuff needs to be super strong.

as the salt water or nasty fresh water can and will eat aluminum fast and or non specific gaskets.

i have seen few intake pics of non marine rated intakes rotted away from salt water use. the correct intake is bronze lined on the inside if i recall correctly.

so make sure your boat stuff is rated for marine use.
 
You will be money ahead and have less headaches if you go this route
http://www.usenginesinc.com/Marine-Engine/Mercruiser-Marine-Engine.html

By the time you get a motor and build it strong enough to live in a boat you will have this much money at least in it. $2500 for a direct replacement 300hp 350cid MARINE motor is far cheaper than where your headed. car motors are NOT the same as boat motors. they look the same and will bolt in but thats about it. search for a 350 marine long block on any site you think you can trust and go that way. dont use a junk yard motor for your own sake..
 
sweetk30 said:
the correct intake is bronze lined on the inside if i recall correctly.
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:whistle:



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:haha:


they don't make em much that way any more.. haven't seen a factory released one in awhile... expensive as heck....

other than this one sitting in my living room, the last ones I played with was putting a new pair on a pair of HO merc 454's from the mid, late 80's.. they where $1200 a piece! :eek1: :doah:



oh, and boats bring the ghey... :deal: :haha:
 
Hey Ryoken, I invoked your name over in this thread in the lounge.

http://coloradok5.com/forums/showthread.php?t=282270

The other day.
Post 31, I believe.
However I misspelled it, so thats probably why you didn't hear me......

Anyway, a couple of years ago, they were hawking a "salt neutralizer" that you mixed with water and used to flush your engines after having them in the Gulf or bay.

I never got around to using it, but I remembered it when they were talking about salt worries.
Figured you could give the correct the answer.

Since salt is Sodium Chloride, I don't know of much of anything that will react with it to bind it or change it so that it does not cause rust.
 
I've seen a few bottles here and there, but i personally have never used it... it's not my job, i don't own a boat...

I have about a 1/2 dozen boats in the yard that have freshwater flush systems on the motors.. and I'd bet the farm, not a one gets used... back when i was playing with the hotrods more, i saw em all the time... and we used em..

just freshwater seemed to do a decent job at washing the salt out.... I'm sure that new stuff helps.. the other aspect of that is that if the boats get trailered, as the hotrods usually are, your a LOT more likely to flush the motor...

also, the biggest thing is whether it's a raw-cooled, or a freshwater cooled system.. and if fresh, 1/2 or full... if it's a full system, ya only have saltwater in the heat exchanger and elbows....

f*ck that Fla stuff... every time i have to deal with barnacles or bottom growth, i think "hey, i could be in Fla!" where it all grows year-round... probably get more of a salt issue too due to the water temps, etc...

not that i don't see a bunch of salt hammered stuff.... :eek1:
 
nsxxtreme said:
I didn't know there was such a thing as a "marine" gasket set what's the difference?
Click to expand...

Up here I've used standard passenger gaskets with no issues, but the marine stuf is way better against corrosion. Since the lack of antifreeze as protection.
Salt water they are a must. But fresh water, can get away with a lot
 
63chevyll said:
Up here I've used standard passenger gaskets with no issues, but the marine stuf is way better against corrosion. Since the lack of antifreeze as protection.
Salt water they are a must. But fresh water, can get away with a lot
Click to expand...

My boat is an open bow wakeboard boat. It won't be seeing saltwater anytime soon. It's a fresh water boat only.

I've seen the marine parts such as intake manifolds and carbs. I haven't seen "marine" gaskets before.

Someone else doing the same things as me
http://forums.chevyhiperformance.co...94-150-valves-ported-on-a-350-boat/index.html

I think my boat has a 10:1 or 11:1 compression ratio now, I can only run premium in it as it pings like a mofo the one time I stuck regular in it.
 
I know they can be pricey but, can he run a heat exchanger to aviod the corrosion in the engine?
 
I stole this from the internet,

Yes, It just has to be a Stainless steel mesh instead of steel, You can get buy with the 1003 with fresh water only. Even with the salt water, the 1003 will work fine but you will have to rinse the engine out every time after use in salt water. Same for Brass freeze plugs, needed only for Salt Water. Here is a fact, unhook the battery cables when in storage, this will keep everything neutral and even with salt and fresh water, the engine gaskets and freeze plugs will last twice as long.

and this

http://www.hardin-marine.com/p-11743-xtreme-marine-seal-cylinder-head-gasket-sbc-4125-bore.aspx
 
63chevyll said:
http://www.hardin-marine.com/p-11743-xtreme-marine-seal-cylinder-head-gasket-sbc-4125-bore.aspx
Click to expand...

Cool thanks I'll book mark that.

What about the gaskets that don't contain metal in them is there any difference?

The desire to use the 305 heads that are on my boat now is so I can run the marine heads and marine intake manifold. The only thing "non marine" would be the short block. Which I would put the correct freeze plugs and whatever else I can find that would make it "more marine".

The cooling system on my boat sucks the water straight off the lake/river.
 
It is not only the corrosion problems that make a marine motor different. Take any car motor and runnit up to 3500-5000 rpms ALL DAY. they will not last. I've had friends do it. They usually lose the lower end first trip out. You will have to build the h3ll out of the short block to make it last. and remember that the cam has to be a marine grind. Just my .02.
Other than that good luck:waytogo:
 
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