rebuilding a 273 180 HP engine

Pick up a copy of:
How To Rebuild Your Small-Block Mopar
By: Don Taylor & Larry Hofer
Copyright: 1982, Fisher Publishing
Soft Back
ISBN: 0-89586-128-3

That will give you the total overview. You should have no problems. The pistons for the 180HP engine are fairly easily located. As mentioned, everything else is just small block Mopar stuff.