Engine upgrades 5.7 383 etc

[wellcraft-classic210]

Gents
I am trying to get me head around the 5.7 engine swap vs upgrade Pro's & Cons ( Does this seem about right ? )

Curious about fuel consumption or other related cost factors as well


I must admit I really like the idea of a 383 and more power but the practical side of me is not sure about the cost and fuel consumption. Any input to help me decide would be appreciated as it seems I cannot afford both professional counseling and boating. :blue:



This would be a direct replacement for my current Gen1 1983

Brand new GEN 1GM Crate motor $1800
Freeze plugs & gaskets ( $300 )
( total part cost $2100 )


Going with a newer Vortec roller design would be more durable engine with more power

Brand new GEN2 GM Crate motor $2000
Flywheel used $100
Intake new spread bore $300
freeze plugs & gaskets ( $300 ? )
( total part cost $2700 )




Brand new 383 GM crate motor $4700
Flywheel used $100
Intake new spread bore $300
freeze plugs & gaskets ( $300 ? )
( total part cost $5400 )

 

[thumpar]

Fuel consumption only goes up if you use the extra power you have. If you drive it just like the 5.7 you may find it gets a little better fuel usage.

 

[alldodge]

Fuel consumption only goes up if you use the extra power you have. If you drive it just like the 5.7 you may find it gets a little better fuel usage.

Agree

 

[Scott Danforth]

all internal combustion motors in boats burn about 0.4# of fuel per HP per Hr.

economy is directly related to where you put the throttle and how much power is required to move the load at the velocity you want.

As thumpar mentioned, the stroked SBC will probably get slightly better economy than the 350 if driven reasonably

you can build a new 377 (6.2) long block for about $2300 (virgin bore, 3.75" stroke). about $2200 for a 350 (5.7).....thats new block, new heads, new rotating assemblies, etc.

a 383 is a 4.030" bore (0.030" over ) 3.75" stroke (+1/4") SBC. these are generally done with used blocks needing to be bored. about same price to source a good used block and have it machined as it is to buy a new block already machined.

for $5400 you can build a 500+hp big block or a 500+hp supercharged small block

build what you want.

if it was me, I would be scouring craigs list. plenty of stroked SBC's (383's, 396's and 406's) being sold dirt cheap because someone lost their job and need to liquidate toys.

In fact after I finished my 468 build, I could have picked up a 509 or a 540 for less money than I had in the 468. I did the 468 for less than $3k. (Exhaust is a different story)

 

[Scott06]

You have the wrong hobby if your worried about fuel consumption, but it's entirely related to throttle position. Not gonna notice a difference between the engines above only cruise vs WOT.

To me it comes down to how much you want to spend and or how much you can get away spend with other people in your life...

difference between the non non vortec and vortec is a no brainer. The 383 I'd be concerned about drive reliability and if you will run out of prop pitch in the normal range -23" (assuming your drive is a alpha 1.5:1?).

 

[wellcraft-classic210]

Great feedback -- It sounds like a well tuned engine of this nature has a basic cost per HP and that's really what i was curious about

Scott
Per your fedback -- you can build a new 377 (6.2) long block for about $2300 (virgin bore, 3.75" stroke). about $2200 for a 350 (5.7).....thats new block, new heads, new rotating assemblies, etc.

6.2 seems interesting -- can you elaborate on how to build a 6.2 for $2300 // Craigslist suggestion is a god point also.