What is the engine serial numbers on the two engines?
Does one or the other or both of you engines have hydraulic lifters (we can tell from the engine serial number) - these were used in all 56 and later car engines. Hydraulic lifters might be quieter than mechanical lifters (which were used in all truck engines). Have you adjusted the valve lash?
In general, yes the engine will sound like certain old sewing machines. Noisier or quieter depending on the shape of the brand/year/shape of the sewing machine, and the condition of the engine and on the condition of the valve train and the adjustment of the valve lash.
