Need a little help with a Chevy 350 block code. It is casting number 3970010 which comes up as 69 to 79 car, truck, vette. It is 4 bolt main and according to my sources was used in 3/4 ton up trucks. It also has bronze sleeves in the lifter bores which I have only seen in truck blocks and a small 010 under the timing cover which should make it a high nickle block. I'm having a little trouble with the code stamped on the front deck p***enger side pad. It reads K12 20 TRH. I know K is the plant in St Katherin, Ontario, 12 is the month, 20 is the day of the month. T is the vehicle type code which I ***ume means TRUCK. RH is supposed to be the engine code, but I have no clue what it means. Can anyone out there help?
It's a truck engine, if you want to figure out what year it is look for the casting date code which would be on the back, similar to where you found the 3970010 number. The date code will have a letter and two to four numbers, like L 8 2 which would translate as December 8, 1972 The TRH code was used in 71 but was probably used again later for a different application. A = Jan, B = Feb, etc.
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