The bores for the push rods on my 1918 block measure .421" diameter. How can this be? I thought standard hole size is .437"
Once in a while you might find a engine with under size push rods. I have had 2 engines like that and have heard of others. Do not know why.
I also have rebuilt a couple blocks that had undersize push rod bores. Just ream them out to standard with a 7/16” reamer.