HT383 crate engine?

[E22]

Looking to build a 383 stroker for a straight inboard application. I have a low-hour, vortec block that is a great candidate for rebuilding but then came across the HT383 crate engine from GM.

My goal is for a cruiser-type build, to maximize low-end torque and durability. It looks to have all the right specs - good cam, 9:1 compression ratio, etc. - but GM adds a "not intended for marine applications" note to the description. Outside of the freeze plugs and maybe the oil pan(?), are there any other obstacles to moving all my components over to this block? What am I missing?

 

[E22]

Here are the specs:

• Horsepower​

  323 HP

• Torque​

  444 LB-FT

• Tech Specs​

  Engine Type: Chevy Small-Block V-8
  Displacement (cu. in.): 383
  Bore x Stroke (in.): 4.000 x 3.800
  Block (P/N 88962516): Cast-iron with four-bolt main caps
  Crankshaft (P/N 12489436): 4340 forged steel
  Connecting Rods (P/N 12497624): Heavy-duty PM steel
  Pistons (P/N 12499103): Hypereutectic aluminum
  Camshaft Type (P/N 14097395): Hydraulic roller
  Camshaft Lift (in.): .431 intake / .451 exhaust
  Camshaft Duration (@.050 in.): 196° intake / 206° exhaust
  Cylinder Heads (P/N 12558060): Vortec iron; 64-cc chambers
  Valve Size (in.): 1.940 intake / 1.500 exhaust
  Compression Ratio: 9.1:1
  Rocker Arms (P/N 10089648): Stamped steel
  Rocker Arm Ratio: 1.5:1
  Water Pump (P/N 88894341): Cast iron
  Recommended Fuel: 87 octane
  Ignition Timing: Base 10° BTDC, 32° Total
  Maximum Recommended rpm: 5000
  Balanced: External

 

[Scott Danforth]

Head gaskets, core plugs, water pump will need to be changed

You could go to a better cam, or switch to 1.6:1 rockers. The cam in there is a bit mild, even for a boat

 

[Bondo]

Looking to build a 383 stroker for a straight inboard application. I have a low-hour, vortec block that is a great candidate for rebuilding but then came across the HT383 crate engine from GM.

My goal is for a cruiser-type build, to maximize low-end torque and durability. It looks to have all the right specs - good cam, 9:1 compression ratio, etc. - but GM adds a "not intended for marine applications" note to the description. Outside of the freeze plugs and maybe the oil pan(?), are there any other obstacles to moving all my components over to this block? What am I missing?

Ayuh,..... Welcome Aboard,...... If I was gonna buy a nearly drop in crate motor,....
That one is My dream,....

If I was buildin' a 383 with my local machine shop,....
I'd build it quite abit differently,..... startin' with deck height, 'n piston shape,....

 

[jimmbo]

"...but GM adds a "not intended for marine applications" note to the description."

Perhaps that little Tidbit is Important... but it is your Money and Time...

 

[E22]

Yeah I guess I was looking to take a shortcut. Let me ask you guys this - back to stroking my current motor, are you aware of any off the shelf stroker kits that get me a 9.0+/- CR while keeping my 64cc vortex heads? everything I’m finding gets me to a 9.4 minimum which is too high I believe for 87 octane. The numbers say I need a piston dish of 28cc+ to get the CR down (with a reasonable quench) and I’m coming up empty on finding them.

 

[Scott06]

Yeah I guess I was looking to take a shortcut. Let me ask you guys this - back to stroking my current motor, are you aware of any off the shelf stroker kits that get me a 9.0+/- CR while keeping my 64cc vortex heads? everything I’m finding gets me to a 9.4 minimum which is too high I believe for 87 octane. The numbers say I need a piston dish of 28cc+ to get the CR down (with a reasonable quench) and I’m coming up empty on finding them.

Stock marine 5.0 and 5.7 are 9.4:1 so dont see an issue with 87 and 9.4 CR