Crank Bolt size.
 

I need to know the "socket" size for a front crank bolt for a Big block and small block chevy, i beleve the small block is 9/16 by memory but could be wrong, Thanks!

Re: Crank Bolt size.
 

SBC takes a 5/8" socket, BBC takes a 15/16" socket.

Re: Crank Bolt size.
 

Thank you!

Re: Crank Bolt size.
 

Ummmm I would say a BBC uses a 3/4" socket since it is a 1/2" bolt. Maybe 13/16" at the most......it's been a while since I've had a BB balancer bolt out.

Re: Crank Bolt size.
 

Ok thanks, i just don't want to pack the whole set..

Re: Crank Bolt size.
 

Also keep in mind after market, such as ARP or Moroso, are different sizes.

Re: Crank Bolt size.
 

at least you weren't trying to figure out the shank size and thread pitch. its quite an odd ball with shank size and pitch

Re: Crank Bolt size.
 

I just installed a 396/TH400 in a 65 Impala SS, The bolt had a 15/16" head & a 9/16" thread I guess it was drilled out?

Re: Crank Bolt size.
 

That could be if someone stripped out the original threads. I just went out to my Suburban and checked.....3/4" socket fits.

Re: Crank Bolt size.
 

Or different cranks, stock and aftermarket? Its no problem anymore guys, thanks for the help!

Re: Crank Bolt size.
 

Hi All,
Do any of you know the thread size of the bolts that are used on the actual crank where it connects to the flexplate on a 402BBC?
Thanks in advance.

Re: Crank Bolt size.
 

They are 7/16"-20. Just be sure you don't use bolts for a flywheel as they are too long and will ruin your block if you run it that way.

Re: Crank Bolt size.
 

Flexplate bolts are shorter than the "flywheel" (manual trans) bolts, they both are the same size but the flexplate bolts are shorter, the longer bolts if used on a flexplate will come into contact of the block and rear main cap causing issues you do not want.