Crank numbers

[Ian]

Today while we were putting the pan back on our motor I noticed a few numbers on the crank "3521" can anyone tell me what these numbers mean? The crank is out of a standard stroke 454.

[Infomaniac]

3521 454 - 502 forged, cross-drilled, 5140 steel

[Ian]

Thanks for the reply infomaniac, what is your opinion on this crank, it is completely balanced. I don't know much about the ratings on steel, is 5140 good? How does it compare to 4140? I'm assuming my motor is an LS7 because of the crank, dimble rods, and rectangle port heads, ofcourse the pistons were replaced with TRW D-cuped pieces. Is this assumption accurate?

[Infomaniac]

You guys have been running those parts for quite a few seasons.
They should be crack checked.
Those are good parts for "stock" parts. As long as you do not intend on adding a lot more power to it, crack check and measure everything and put it back together.

[Ian]

The motor has been together for quite a few years, but actually has very few hours on it. When we got the boat the motor had about five hours on it, and we've since put about 10-15 hours on it. When we bought the boat it had been sitting for quite a few years, because the guy lost interest in it shortly after building the motor.

[Infomaniac]

Sneak a peak at the number 2 main bearing just for the hell of it.
I know you guys do not intend to tear it down.