I have a small block crankshaft that I got years ago that I was told at the time was a forged crank from a 340. I never bothered trying to verify it until now. The part number on it is 2658278 which according to the one chart I looked at is a 273-318 cast crank. However, based on the picture in the tech section showing the differences between cast and forged cranks it would appear it is a forged crank. It has the wide parting lines and the rounded edges but the part number looks more like that of a cast crank.

Tech picture.

I thought the 273 had a forged crank ?

Can you post a better , not so dark , picture of it ?

forged, if you ask me

the edges look rounded on your orig pic so......... .......... forged crank

I don't know if it will help but here is another picture.

Forged for sure

what they said

Yup, forged.

Can someone verify if the part number is for a forged crank? In the attached chart it indicates the part number on the crank I have as being a cast crank.

http://kim_spure.tripod.com/A-Engine.htm#Crank

now, which damper go with which crank?

yup. it's forged...273 or 318. the 340 had the rod journals cross drilled. interchageable with a balance job.

Regardless of the P/N, that is a forged crank. It's easily determined by the wide parting line because it was slammed between two dies in a forge. If the two dies hit each other, the forge will destroy itself, so the dies stop short and leave a wider seam. The cast crank has a thin parting line, because the casting molds are held together tightly so the molten steel doesn't run out.

O.K. Thanks everyone.

I, too, am curious as to the part number, is it stamped or written or is the number raised?

Here is a picture of the number. It is raised but there are a couple of other numbers and letters that are stamped.

Stamped numbers and letters.