If I had to track down a commercial product, search the catalog listings (duh).
BUT: check the part number to see if it's also listed for other not-very-similar engines.
An L6 won't match any V8, but a 194/230/250 is probably not identical to a 292 - the extra stroke does quite a lot - and the RPM at the same "danger points" will be somewhat lower.
In L6s, the entire arrangement of weight in the crank is different between 4 main bearings and 7, and I suspect it affects stiffness.
Anything that reduces stiffness (smaller bearings, longer stoke, longer crank) reduces the RPM at these points, but exactly how much is the $$$ question.
BHJ advertises one specifically for the 235/261 (which have the same dimensions in the important stuff).
