Thread: 383 stroker

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What exactly is a "stroker" motor? Why are they 383's?
Thanks,
Brian

As you know, the stroke of an engine is a function of the crankshaft ONLY. The stroke is the distance that the piston moves in the bore. The stroke has NOTHING to do with the length of the rod, the rod only connects the piston to the crankshaft.

A "stroker" is slang for any motor that has had its stroke changed. IT can be "stroked" or "destroked".....destroked meaning that the stroke is lessened.

A 350 Chevy has a crankshaft with a stroke of 3.48 inches. If someone were to put a longer stroke crank in that motor, the diplacement would change. A 383 is a common "stroked" 350 size since it can be accomplished with a crankshaft from a larger displacement 400 chevy engine......i.e. easy to do and relatively cheap.

hope this helps

Without getting technical, it's a 350 with a 400 crank, etc. in it.

Brian, a stroker motor is one which has had a longer stroke crankshaft installed to increase power. It adds cubic inches which will increase power and the longer stroke will increase the leverage on the rod journal of the crank, creating more torque.

The optimum and most popular combination seems to be the 383 chevy small block. The stock bore and stroke on this motor are 4.000" for the bore and 3.480" for the stroke, resulting in 350 cubic inches. By boring the block 0.030" and using a 3.750" stroke crank, we get a bore of 4.030" and a stroke of 3.750", resulting in 383 cubic inches.

You can have a small block 400 crank main journals turned down in a lathe from 2.650" to 2.450" so the 400 crank will fit in the 350 block or you can buy an aftermarket crank from several suppliers such as Scat.

The stock 350 reciprocating assembly was internally balanced by adding or subtracting weight to the crank counterweights, while the 400 crank was externally balanced using offset weights on the harmonic damper on the front of the crank and an offset weight on the flexplate at the rear of the crank. So, when using the 400 crank in a 350, you have to use the 400 damper and flexplate in order to properly balance the motor.

You can change the crank in any motor to one with a longer stroke, thus making it a "stroker" motor. You can also offset-grind a crankshaft on the rod journals and use a rod with a smaller "big end" to fit the new rod journal diameter. Or, you can weld up the rod journals on a crank and grind them further offset, using the stock rods and a piston with a different compression height.

Speaking of pistons, you must use a different piston with any stroker crank if you're using the stock rods, to prevent the piston from being pushed out of the bore at top dead center. The dimension from the center of the wrist pin to the top of the piston will be shorter on a stroker.

Scroll down the left side of this link page and pick out the stroker combinations to get an idea of what's available.....
http://www.speedomotive.com/