Working on the assembly of my 371 over the weekend, I measured crank endplay at .010-.012" using a large pry bar between counter weights and #2 main cap. GM spec is .0015-.0078". From what I read, most builders like .005+ on a performance build. However, I can't seem to find much info on effects of thrust being over spec other than possible clutch engagement problems on manual cars or crank trigger issues at high rpm with end play being way out of spec (.025+).
How much force is needed to get accurate end play measurements?
Any adverse effects from .010 thrust?

 

Bump for the engine builders that may have some insight on this.

 

I was unable to find anything on this for you. I was really hoping that 1fastbrick would respond as he is one of the most knowledgeable on here about this stuff. If you dont feel confident with what you have you could always order an oversized thrust bearing. You might even want to start a thread on yellowbullet.com as there are very knowledgeable engine builders there. In for the results. Good luck