Engine identification help?

[stacerbob]

Just got a 64 c10 recently, guys dad bought it new, have the original title. He says it's the OE engine, although it is mostly orange, not grey. The casting number on the back is 3849852 indicating it is a 64 283 but the front stamp does not have part of the vin but ha F0526m
Plain as day it doesn't look like it's ever been surfaced, easy to read. I have been on nastyz28.com but can't find that exact number there

Any other ideas on where to verify?

[LT1 Burb]

M codes as a 58 283, should be MX for manual and MY for power glide.

[Captainfab]

That casting number shows as a '57-'66 283. So a M code '58 283 sounds correct.

[60-66]

The single letter "M" suffix shows in the "Chevrolet Truck" parts book as being used from 1958-1964 , from 1965 on, it was not used. That block casting number was used in trucks only from 1963 through 1966 and in passenger cars from 1964-1966. 1958-1962 283s were a different casting number. To be conclusive on this you need the blocks casting date which will be on the back of the engine by the bell housing , this will show the exact year which could be a "3" for 1963 or "4" for 1964. Suffix "M" decodes as C10 C20 C30 K10 K20 283 manual trans.

[stacerbob]

Well it sounds like it probably is the original engine, just have to find the date code.

Thanks for the help