Need Help on Bolt Size

[Speedbumpauto]

Any of the ones I've done, mostly V-8's use a 5/16 NF(24) on that water pump flange. That and the crank pulley to balancer are the few fine thread bolts on that vehicle.

[Divine 59]

On a 235 the bolts will be fine thread.

[mr48chev]

Originally Posted by Speedbumpauto

Any of the ones I've done, mostly V-8's use a 5/16 NF(24) on that water pump flange. That and the crank pulley to balancer are the few fine thread bolts on that vehicle.

Yes, I've never seen a small block pump with anything else.

I've never seen one with 1/4 inch bolt holes either.


In case you can't eyeball a bolt and tell it's diameter, outside of a few odd ball bolts the following almost always holds true.

1/4 inch bolt = 7/16 wrench
5/16 inch bolt = 1/2 wrench
3/8 inch bolt = 9/16 wrench
7/16 inch bolt = 5/8 wrench but often has a nut that takes a 11/16 nut.
1/2 inch bolt = 3/4 wrench

The larger sizes can be mix and match so I left them out.

[dwcsr]

My mistake. Yes 5/16