[Bored&Stroked]

It depends on the crankshaft, desired stroke, process used, etc.. The most typical example in our Flathead world is taking a late Mercury 4" stroke crankshaft - which has 2.138 journals and offset grinding the journals down to a 1.999 1939-1941 221 cubic inch flathead size. By doing an offset grind, you can increase the stroke to 4.125" - then you used the 39-41 91A/21A rods and the smaller 1.999 full-floating bearings and you were good to go.

This was how guys created the standard "full-race" flathead --- with a 3 3/8 bore (3/16 oversize) and a 4 1/8 stroke crankshaft, you now turned a 239 flathead into a 296 cubic inch flathead.

Now - outside of this example, there were a lot of custom crankshaft shops in the 50's/60's that would weld up a regular crankshaft (to essentially move the journal further out), then offset grind the welded up journal, to achieve a big stroke. Shops like "Reath Automotive" in Long Beach would weld and offset grind all sorts of different cranks to increase the displacement of many different engines. A great example is the Early Chrysler Hemi - they'd take a 392 cubic inch engine and stroke it to 450 or so cubic inches (all due to creating "welded strokers").

In our modern world, we have custom billet crankshaft shops that basically carve you out the crankshaft you need, with the journals/rods you want to run and can make dang near anything (that fits in the specific engine package). You just don't see that many "welded strokers" these days. Of course these custom billet cranks have a long lead time to produce and have a very high price tag. $2500 on the low end . . .