318 stroker motor 330 HP 349 cu.in.

Engines, Shafts, Steering, Struts, Rudders, etc.
Trowerpower
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Location: Northern Kentucky

Re: 318 stroker motor 350hp 390 strokers

Post by Trowerpower »

We test run the 390 stroker motors Thursday and all went well for five hours on the little tenn. River until the starboard engine developed an electrical short and developed a slight oil leak somewhere on the top of the engine. 4000 rim developed 26 knots and she topped out at 4500rpm at 33 knots or 36.3 mph.ort motor ran perfect which now has 10 hours on it. It seemed to plane at 2200rpm. We installed Flowscan fuel meter and was using 3gph at 1800rpm or 12mph per engine. It sounds just like it did before the rebuild until the four barrels kick in on the Edelbrock 1410's -750cfm carbs. It comes out of the hole great with the stock16/15 props. Port motor has 10 hours on it now and it ran great all day.more updates after the repairs are made to the starboard motor.
Trower Power
1987 32ft Marinette Sedan Flybridge
Blue Sky
twin 392 Chrysler Stroker Motors
Performance Distributors
750 Edlebrocks
fresh water cooled
1.5 to 1 velva-drives
Onan 6.5kw gen set
Fastjeff
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Re: 318 stroker motor 330 HP 349 cu.in.

Post by Fastjeff »

Look for loose valve cover bolts.


Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington
Trowerpower
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Posts: 174
Joined: Sun Dec 07, 2014 8:50 pm
Location: Northern Kentucky

Re: 318 stroker motor 330 HP 349 cu.in.

Post by Trowerpower »

Ran the boat last Thursday 4300rpm at 36 mph was tops. Starboard motor pushed out a head gasket, limped back to Harbor Towne Marine on the port motor. Head gaskets replaced today so more testing coming soon. I suspect the head bolts are bottoming out when they torque the heads or they are not using a .040 composite gasket.
Trower Power
1987 32ft Marinette Sedan Flybridge
Blue Sky
twin 392 Chrysler Stroker Motors
Performance Distributors
750 Edlebrocks
fresh water cooled
1.5 to 1 velva-drives
Onan 6.5kw gen set
Tranquilo
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Joined: Mon Sep 08, 2014 8:55 am

Re: 318 stroker motor 330 HP 349 cu.in.

Post by Tranquilo »

You'd think they would know about that...

Keep posting. I'm very curious how these stack up against stock. The HP difference is huge but that doesn't always translate to performance.

Sounds fast as hell
2x 1973 28 Express - Single 318
New electrical panels, water system and velvet drive
Miami FL & Catawba OH
Joe
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Re: 318 stroker motor 330 HP 349 cu.in.

Post by Joe »

Hello, First I am not trying to be negative, Just trying to under stand. You went back with the 318s? , and put a stroker kit?. They dino at 330hp?. They "MAXED" out at 4300 to 4500? . Running stock props 16/15 .If sow ,than something is wrong!. A stock 32 FBS marinette with 318 240hp clean will turn 4300 to 4600 run anywhere from 33 to 36 mph. I was out last sat with 4 adults, 4 kids, 3/4 fuel ,topped off fresh water, Full cooler ,and all the crap you could bring, The boat has not been out if the water in 3 years and got it up to 4000 ,turning stock 16/15 props. with gernerator and the aluminum aft deck I added. With a true 660 hp ,and right props you should be hitting 45mph. Joe
1988 sedan flybridge. Black / White. 318 240 hp Aluminum aft deck hard top. Louisville Ky . Tartans landing. " KNOCKEFELLERS"
Fastjeff
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Re: 318 stroker motor 330 HP 349 cu.in.

Post by Fastjeff »

Not....really. A 25 % increase in hp only produces a few more mph. Also, that hull is not designed for going fast--honestly! (Hydrodynamic hull design is a black art understood by very few.)

A case in point: My 1985 Bayliner would not go over 30 mph--and even with a supercharged, 502 Mercruiser! Later versions of the same boat easily hit 40 mph with an identical 350 SBChevy (a 315 hp. Marine Power). Over the winter (being anal) I crawled under both boats (they on blocks--come on now!) and photographed the two hulls. Other than a slightly different design of the strakes, they 'looked' identical. Sure as hell didn't run that way!

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington
Tranquilo
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Re: 318 stroker motor 330 HP 349 cu.in.

Post by Tranquilo »

So you are saying that you will have a similar result going with a tuned up stock 360, rather than a stroker 318 due to the hull design?

Drag and shape are very important (trim tabs help a bit). So is weight, clean bottom and load balance at top end (as I have found).
2x 1973 28 Express - Single 318
New electrical panels, water system and velvet drive
Miami FL & Catawba OH
Tranquilo
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Posts: 245
Joined: Mon Sep 08, 2014 8:55 am

Re: 318 stroker motor 330 HP 349 cu.in.

Post by Tranquilo »

Here is another thing that I know goes into boat design with larger ships: Transmissions, props, and blade speed.

I know that my single 318 with a 1:1 isn't going to gain that much by turning it an extra 500 to 1500 rpms at top end. This is because the slip on my prop will likely increase as I go faster.

I'm willing to bet that the guys with 1:1.5 transmissions and larger, more aggressive props can keep the prop in the right speed/efficiency zone than the less aggressive props with more RPMs. That would put the extra horsepower to work more efficiently.

I'm an idiot when it comes to boats but I spend a ton of time in the water pushing myself around to know when the right amount of effort to movement is achieved for the fins or paddles I'm using. Longer fins are harder to push but you don't require the same amount of kicks. Don't believe me? Get in a pool without fins, swim a lap and put fins on and do it again (even tired). Maybe that is a stupid theory but I'll fight you all on it anyway! :lol:
2x 1973 28 Express - Single 318
New electrical panels, water system and velvet drive
Miami FL & Catawba OH
Trowerpower
Aluminum Star
Posts: 174
Joined: Sun Dec 07, 2014 8:50 pm
Location: Northern Kentucky

Re: 318 stroker motor 330 HP 349 cu.in.

Post by Trowerpower »

Good evening! Our old girl picked up 10mph with engine rebuilds. Awesome!
Trower Power
1987 32ft Marinette Sedan Flybridge
Blue Sky
twin 392 Chrysler Stroker Motors
Performance Distributors
750 Edlebrocks
fresh water cooled
1.5 to 1 velva-drives
Onan 6.5kw gen set
Tranquilo
Royal Aluminum Star
Posts: 245
Joined: Mon Sep 08, 2014 8:55 am

Re: 318 stroker motor 330 HP 349 cu.in.

Post by Tranquilo »

Thats what I wanted to hear!
2x 1973 28 Express - Single 318
New electrical panels, water system and velvet drive
Miami FL & Catawba OH
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