[beater68427]

I see would need the number from the top of piston. That Block with a 14 and 8 digit would be a late 70's the crank number is missing a number should be 39411182 Steel crank number used in truck all years with 2pc seal and I believe in early Z28. The 492's are angle plug I believe. Sounds like someone used a late 70's 4 bolt truck engine to start with.