engines

[Tyler Mitchell]

What is a 383 stroker? I couldn't find any information on it, but I'm pretty sure it wasn't an original 'vette engine. Thanks to anyone that can help-Tyler

[Joe L.]

Re: engines

Tyler-----

A 383 cid engine was never originally used in a Corvette or as a PRODUCTION engine in any Chevrolet. A 383 is, basically, a 350 cid block (4.00" bore) with a 400 cid crank (3.8" stroke). Since it is, essentially, a stroked 350, it is often referred to as a "stroker". GM now offers a crate SERVICE engine made up to these specifications, but such a configuration was never used in PRODUCTION.

[Duke W.]

Re: engines

Most 383s built from vintage SBs start with a .030" over bore (4.031') combined with a 3.75" stroke crankshaft, which are readily available on the aftermarket.

As far as I know, only GM offers a 3.80" stroke crankshaft to yield 383 CID with a standard 4.001" bore.

A 383 makes a nice combination for the street because the increased displacement yields considerably more low end torque. Since volumetric efficiency and bottom end stress are are proportional to mean piston speed, a 383 will run out of breath sooner than a shorter stroke engine with the same heads and cam, but proper cam and head selection will yield 5500 to 6000 useable revs without overstressing the bottom end while still maintaining excellent low end torque. Also, I believe that most vintage blocks will required some machining to provide sufficient clearance for the longer stroke crankshaft along with increasing the main bearing bore size.

Duke

[Clem Z.]

Re: engines

one of the reasons a 383 feels so responsive is because the velocity increase thru the std size SBC intake ports because of the larger displacement. this adds to the feel of power.

[David Bodily]

Re: engines

By using the 400 cid crank does this mean the engine is converted to externally balanced?

[Joe L.]

Re: engines

David-----

Yes, the use of the 400 cid crankshaft results in 383s being externally balanced. A special balancer and flywheel/flexplate must be used with 383s UNLESS the crankshfat is re-balanced and converted to internal with mallory metal.