Crank "tabs" on a 413 ?

[bandit67]

Guys in my " freshly aquired parts department" I noticed these tabs on a crank that is marked 413. They do not look welded on but I was thinking some one done that in the past in doing a balancing job. Those were not on there from the factory, correct?

 

[R413]

Those are factory, it’s made that way. They don’t really bother anything on a stock engine. They can be cut off, will need to rebalance the engine.

 

[RemCharger]

They are there, to balance.

 

[bandit67]

Ha ha, learn something new everyday. Were those strictly for a 413 crank or was that done on others as well. I am assuming those holes drilled in the outside of a throw flange was the results of machine shop rebalancing job?
I am pretty sure that crank is steel but my book says those numbers, as best I can read them, should be cast iron. Steel or Cast?

 

[RemCharger]

Forged steel. I have 1, and if you do a crank "ring" test, compared to 440s, it seems to have a higher/tighter frequency . It would lead you to think its a better material. But I'm not a metallurgist .

 

[Challenger340]

Them 413 Cranks were some kinda tough sum-******* !

We wailed on one with a Tranz-brake for 15 years at 600+ hp..... never hurt it.... never a crack.... and even WITH the rolled fillets same as a 440 Crank ?

Pounded the SNOT outa the #4 Main on TWO Blocks over that same time.... but that Crank stayed puss ?

Got me wondering about the metallurgy as well because I can offer no explanations ?

 

[andyf]

Guys in my " freshly aquired parts department" I noticed these tabs on a crank that is marked 413. They do not look welded on but I was thinking some one done that in the past in doing a balancing job. Those were not on there from the factory, correct?

View attachment 1107905

Yeah a lot of 413 cranks have those tabs or sprues left on. Not sure why, maybe the 413 cranks were made by a different vendor. I don't recall ever seeing the tabs on a 440 crank but I've seen them on a lot of 413 cranks over the years, especially the earlier ones.

 

[padam]

My 64 413 crank has them

 

[padam]

They actually have what looks like jaw or clamp marks on the OD, so maybe the early mfg process was different.

 

[andyf]

Here is a picture from my archives. This is an early stroker motor rotating assembly from back in the days before you could buy stroker kits. This is a 413 crank that has been turned down and offset ground to make a 470 crank in a 400 block. You can see that the tabs have been cut down and smoothed out. Last I knew this engine was still running hard in an E body car.

 

[padam]

I just had mine magged and ground, and it checked good.

 

[bandit67]

Plans are to haul this one in and see if it can be ground. Has a pretty boogered up throw...

 

[padam]

I just had mine magged and ground, and it checked good.