Paint markings in lifter valley

I opened up my 86 block to start the rebuild and found some paint pen markings over each cylinder in the lifter valley.  Any idea what they mean? Cylinders 1-4 had 4-4-3-4 and cylinders 5-8 had 3-3-4-4 written on them.

Thanks!

Trigged wrote:I opened up my 86 block to start the rebuild and found some paint pen markings over each cylinder in the lifter valley.  Any idea what they mean?  Cylinders 1-4 had 4-4-3-4 and cylinders 5-8 had 3-3-4-4 written on them.  

Thanks!

Pistons are usually sized in TEN thousandths increments for production and it seems like this is the production piston diameters used.

Not sure I follow since the pistons should be 4.360" diameter. Are you saying they should mic out to 4.363" / 4.364" or 4.330" / 4.340"?

He said TEN thousands.

Yes the bore is 4.360, but the pistons aren't oversized, they are undersized for clearance after expansion. Expansion and subsequently clearance when cold is determined by piston material.

Ahhhhh! Too much eggnog clouds the brain. Thanks! That makes a lot of sense! Thanks!