I finally got around to looking at the old crankshaft that came out of my 393 stroker, and noticed it has a 4MA casting mark on it. I thought all the "regular" ones just had 4M. Is this a Boss crank?

4MA is a revised production crank, Boss cranks have a number starting with "D1ZX" i believe it is? electric pencil etched at the rear of the crank.

"Enlightened statesmen will not always be at the helm" ~ James Madison

I've held one in my hot little hands !

what was it then that was electro-graved in?

"Enlightened statesmen will not always be at the helm" ~ James Madison

hand stamped on a couuterweight near the front (#3 maybe). Those that passed the Brinell Hardness test were stamped. A Brinell hardness tester is
a specialty machine that non destructively tests metal hardness, The machine
has a screw jack that "adjusts" a probe to a "0" point on a pressure dial. A
lever that trips a timed release of pressure on the probe. A tattle tale on the pressure dial tells you what the hardness was/is. More exotic versions are digital and give a digital readout. There are many different tip daimeters on the probes for different metals. There are also at least 3 different scales used in hardness testing. A is seldom used, B is used for aluminum and others, while C is typically used for steels and iron.
Cranks without the D1ZX-A that have the domple simply weren't hard enough
for the D1ZX-A specification and weren't stamped.
Randy

IIRC, the boss cranks were just 4MA cranks that tested as having better than average hardness......nothing I'd pay extra for, especially considering the relatively low cost of 4340 cranks these days.

many cranks were tested to qualify at spec, not all tested were assembled into Boss engines. my first Clev had the test mark in a 2V.

"Enlightened statesmen will not always be at the helm" ~ James Madison

And where is it?

so what was the 4MA B crank?i have seen them with a small m/c pad near the number on the front c/w ,and have seen what looks like a brinell ballbearing mark on this small pad . is this anything?

it's a small spot ground smooth on the front counterweight?

with a center punch looking indentation in it. the diameter of the punch mark indicates the resistance or hardness of the metal when compared to the test scale.

http://www.instron.us/wa/applications/test_types/hardness/brinell.aspx?ref=http://search.yahoo.com/search;_ylt=AgUOPlMLc9eiUGDNsN8nYOimN3wV

"Enlightened statesmen will not always be at the helm" ~ James Madison

so It is a brinell mark. but what is the "B"

it's a further production revision

"Enlightened statesmen will not always be at the helm" ~ James Madison

n/m

It used a nodular flywheel and unique damper . the boss had 27.3 oz-in imbalance as opposed to the normal 28.2 . that likely explains the DIZX scratched in the back of the block as well ,so the assembly line personnel would know what to stick in it .

I have one, or that what I ws told, I know it had a Brinell mark, will take a pic, also have matching dampner. I do not remember any D1ZX numbers, will ck.....Tim