Speed Pro/TRW AMC Jeep 401 Forged Dish Coated Pistons+MOLY Rings Kit +30 (.030 bore) AMC/Jeep 401 - 4.195" bore (at +.030") AMC/Jeep 401 - 4.205" bore (at +.040") Good for street or race/nitrous to 150 shot 5/64" 5/64" 3/16" ring grooves Press-fit only Pins