[chuckv]

You might be able to borrow a bore gauge from a local auto parts retailer...

 

[chuckv]

Be aware that there are two versions of the B43G oil pans, with the earlier one having only a bottom drain and no side drain. Your later 318 should have a hole in the frame matching the bottom drain, since the P218 pans have only the bottom drain. Each uses a slightly different dipstick a well.

Chuck