1650 k341 crankshaft
 

Just had my crank reground it had .002 to .004 in.
ware on it .It came back at 1.488 in
should it have been 1.490 ?
will it work ok with a 010. under sized connecting rod ?

I think your machine shop owes you a crankshaft. A properly-machined 0.010"-under crank should be 1.4900"-1.4895". They ground it under the max wear limit for a 10-under throw, which is 1.489".

Since it's at a smaller diameter than the max wear limit, it'll knock and probably not last long. Take it back to the machine shop and have them set things right.