crank difference? one and two piece rear main seals?

[allcarfan]

How can I tell if a crank is for a one or two piece rear main seal block?

Also, how can i tell what 'balance' a crank is?

 

[351LX]

According to this chart http://www.butlers-a1.com/fordm.htm the 50 oz cranks have a 2MAE casting number while the 28 oz ones are 2M or 2MA.All 2M or 2MA cranks will be for a split seal.The 2MAE ones could be for either since the one piece style came out in 1983.

 

[allcarfan]

This is an aftermarket Eagle Crank

 

[D.Hearne]

I believe the Eagle crank works with either type seal. The stock one piece seal cranks don't have a flange ahead of the seal surface.

 

[D.Hearne]

As for balance factor, I couldn't say at the moment. I've got a stroker kit ( 331) at the engine builder's shop now but he hasn't balanced it yet. Any competent machinist that does balance work can balance it to either factor.