I bought new pistons, etc., for my 95" big bore build, which is 1550 cc, of course.

My new Wiseco pistons, size 3.880, 10.5 comp., say .0005 on them, leading me to believe they are .0005 over stock, or standard, or something.

I asked for 95" pistons, 1550 cc, etc.............

Why are they .0005?

And what are they .0005 bigger than........?

What will the machinist be boring my cylinders out to?

 

are you sure it's not .005?.0005 is a half of a thousandth of an inch, more correctly refered to as 5 ten-thousandth. a standard '95 piston usually mikes out to 3.874and change, so 3.880 would be .005 over.as long as your cylinders haven't been sized yet, you'll be fine.

 

.005 is a whole lot bigger than .0005 so if your pistons are .0005 over no big deal
but .005( 5thousandths ) then you might have an issue with piston to bore size clearance
you see most pistons are egg shaped and tapered they have to have clearance. you need
to call the manafacturer and enquire

 

Your machinist will measure the pistons and bore the jugs to match them.