Ist pictured engine serial# decodes as F = Flint assembly plant / 8 = August (month of assembly) / 5 = 5th day of August / Z = 1957 or 1958 Passenger car regular engine with standards 3 speed or 3 speed OD transmission. Per the 1957 GM Heritage Center archive data (and the 1958 data), that 235 came standard with hydraulic cam/lifters. It could have since had a replacement mechanical cam installed, so further checking of the lifters is needed to verify which. Since Chevrolet used the same engine serial number sequence/codes for both years, to confirm if 1957 or 1958, need to know the block casting date code.
2nd pictured engine serial# decodes as 0247780 = 246,780th engine built / F = Flint assembly plant / 55 = 1955 model year / Z = 1955 Passenger car 235 regular engine. Per the 1955 GM Heritage Center archive data, this engine would have come with a mechanical cam/lifters as it was not originally built as a "Powerglide" equipped engine. Those got hydraulic cam/lifters as standard when coupled to the automatic transmission.
Hope this is helpful.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
