What I recall about the 383 conversion articles is that it's so common that the parts cost about the same as 350 parts, although a small base circle camshaft and some grinding of the pan rails are required to accommodate the lengthened stroke.
Nowadays it is common, but back at the beginning in the late 1980's, the only way to create one was by taking a 400 crankshaft and turning the mains down, or buying an $800-$1000 Lunati crank or some other top shelf crank companies. I worked in a pretty large race shop in North Georgia during that era and 400's were not rare or hard to find. It took another 8-10 years after the 383 craze started before companies like Scat and Eagle began to offer cranks for the 383 conversion. And they were still pricey at the beginning, still making a 400 the better bang for the buck.
