383 stroker-gctid805077

[hfxjack]

Looking to repower thinking about a 383 stroker. Looking for opinions and experiences with this engine

Cheers

[Chief_Alen]

You may achieve the same hp but not the same torque.

[BHaven]

I went with the 383 Stroker when I re-powered our 2007 Bayliner 288 Discovery. Absolutely love the performance out of the hole and on long cruises. Have had it on two long shots up to Desolation and up to the Broughtons the following year. Heavily weighted down with supplies on both trips and couldn't be happier with the performance.

[Pcpete]

There's more to getting it right building an engine than just ordering up a 350 or 383. Sure going to a 383 will get more cubic inches, but unless the intake and exhaust system are adjusted too, nothing much is going to happen. This is where someone who really understands marine engines can take an average runner and make an engine system that really performs. It's not done by grabbing a bunch of gee whiz bang super what the drag boat racers are advertising, it's done by considering the boat weight, hull type, loading, gear ratios and customary loading. Things like balancing and blueprinting go without saying as does marine grade or better parts and components. The right cam and carb setup are where to look to those solutions. There's not going to be much that can be done with the exhaust manifolds, so that needs to be considered as well. Obviously Bhaven has a good combination going. Take your time finding the right person to build your engine, ask around at places like a balancing shop, or several marine service providers who's the best choice, or better, who who they would have build them an engine.

[Norton_Rider]

A friend repowered his 1988, 2858 with a 383 stroker marine engine and a Mercruiser Bravo II. The boat originally had an OMC King Cobra 7.5 (Ford 460). At the time I had a virtually identical boat with the OMC setup and an newly overhauled Ford 460. My boat performed well after the overhaul, but his boat would blow its doors off. It would get on plane quicker, it had 5-7 knots more top speed, and it used less fuel. So yes, a marine 383 is a good way to go.

[SprinterX]

https://vancouver.craigslist.ca/bnc/bpo/6087498748.html

[Chief_Alen]

I am of the opinion the B2 drive is the best B drive.

BB Vs SB has been a discussion carried on between people forever.

Yes less weight built correctly ... SB can and will be the correct solution for many people.

Go to Michigan Motorz web site take a peek there make your decision, choose wisely.

I wish you well !

Did you read the add :

2015 350HP 383 Mercruiser with additional cooling system. Just over 200+hours on the engine, in the 200+ hours the oil and filter has been changed four times with mercruisers 25/40 synthetic oil. Fresh water use only. Nothing wrong with this engine. In the end it did not have the power/torque I needed (larger heavy boat) and have settled on a 496. Since swapping this motor out it has been sitting in a covered shop. I initially had plans on putting this engine in a smaller boat, however the setup in that boat is a long way away from failing. Check out mercruisers site about this engine. With the right application this is a great engine with tons of power and torque.

[builderdude]

"Chief Alen" post=805152 wrote:
Did you read the add :

I did and wondered what model he was referring to and if he had the proper gear ratio and prop set up. Might be worth it for the op to send him an email :whistle:

[2850Bounty]

John, a few pieces of info that you'll want to know:

The 6.2L is a 377 cu in SBC that began as a 5.7L.

The dimensions are 4.000" bore with a 3.750" stroke. These are new engines from GM.

The 6.3L is a 383 cu in SBC that began as a 5.7L.

The dimensions are 4.030" bore and 3.750" stroke. These are remanufactured engines.

The 3.750" stroke crankshaft dimension comes from the old 400 cu in SBC that was used mostly in GMC and Chevy trucks.

Either of these above will come with the dreaded GM Full Dished pistons, of which cannot possibly create a quench effect!

This build is also more prone to Maine load Detonation!

In order for the 6.2L or 6.3L SBC to produce great torque, the pistons need to create a Q/E. This means NO GM full dished pistons! :evil:

If you have one custom built, you can go with a piston profile that takes advantage of the SBC cylinder head quench surface.

This reduces the risk of Detonation as well.

No other changes are required.

There will be a slight increase in cost for the pistons alone.... but the assembly is basically the same and will not require any more shop time.

If you go this route, you will now get some good torque from this build.

[hfxjack]

Mercruiser ratings are 390 for the stroker 370 for the 7.4

[2850Bounty]

"hfxjack" post=805549 wrote:
Mercruiser ratings are 390 for the stroker 370 for the 7.4

[color]#000088 wrote:
Are these horse power numbers????

If so, look closely at the RPM at which these are being rated. Most often the RPM is much higher than what we will be operating at.

Example: when GM introduced the Marine version 5.7L SBC Vortec, they gave it a 315 hp rating..... BUT, the rating was acquired @ 5,200 RPM!

Who operates their cruiser at even near 5,200 RPM ???? :woohoo:

Point being....... these Marine hp numbers are often misnomers.

And..... what we want is TORQUE..... not necessarily horse power!

Torque is greatly increased by having an adequate stroke, good combustion chamber design, and the correct LPCP. [/color]

[hfxjack]

390 torque

350 hp

Both at 3500 rpm right in the sweet spot

[hfxjack]

Those first 200 hours are a concern especially when he says it was overloaded replaced with a 496 and no warranty not pay much more for new out of the box

Cheers

[2850Bounty]

"hfxjack" post=805601 wrote:
Those first 200 hours are a concern especially when he says it was overloaded replaced with a 496 and no warranty not pay much more for new out of the box

Cheers

[color]#000088 wrote:
That engine listed on Craigslist is a 6.3L (aka 383 cu in) from Merc, and will have been fitted with the GM full dished pistons.

You can do much better by custom building one. [/color]

.

[SprinterX]

"hfxjack" post=805598 wrote:
390 torque

350 hp

Both at 3500 rpm right in the sweet spot

That's what I saw too John. Seems like a great fit.

2850Bounty has been beating that piston/quench drum for a long time and I also subscribe to it. It could very well be worth talking with a custom builder to incorporate this type of configuration. Jim Richmond in Port Kells is a very prominent engine builder in the area with the racing and hot rod crowd. He has a dyno too.