Do you know which piston was ordered in the kit? Flat or Dish?
Hopefully a dish of about 12cc.
An engine needs careful planning before parts are ordered. Compression ratio, cam timing, vehicle weight, axle ratio, intended usage, transmission, stall(if auto), exhaust, etc to work well together.
1.6 rockers will increase lift at the valve to .544/.564 with that cam. Checking for spring coil bind and geometry is critical.
I would have used no bigger than this with 1.5 rockers for a strong, dependable, daily driven street truck.
http://www.summitracing.com/parts/hr...make/chevrolet