I checked my books (the internet is usually wrong), and that casting number is listed as nothing more than a general-purpose passenger car application, '68-'76.
But keep in mind that engine code suffixes are not always correct, are not fully documented, are known to have been reused on different applications (without documentation), and may be impossible to track down.
For example, both of the remaining SBCs in my garage right now have suffixes that don't match or cannot be identified: APQ ('truck' 350, VIN-matched to a chassis-cab), but there's no record of that suffix anywhere.
And SXA: SXA is a known suffix, identifying an '84 passenger car 190 hp 305. ...Except this engine is a '73 400 out of a truck*.
*(Another VIN match, with another "What the...?" recycling example. The engine was pulled with its original heads. Except, the casting number was only ever used on 327s in the '60s. Don't make much sense, does it?
Well... If you go far enough down the rabbit hole, it comes to light that they were only used on 327s in the '60s, except for that one time when GM got retarded and brought that casting back for just three months in 1973, so they could drill steam holes and slap them on 400s going into trucks with manual transmissions. Why? No idea. ...Just another layer of confusion in the cesspool that SBC casting numbers and codes are.)
It's a date code: [T]onawanda, [03] March, [12], [HD] '69 250 HP 350 w/ TH350.
But keep in mind that engine code suffixes are not always correct, are not fully documented, are known to have been reused on different applications (without documentation), and may be impossible to track down.
For example, both of the remaining SBCs in my garage right now have suffixes that don't match or cannot be identified: APQ ('truck' 350, VIN-matched to a chassis-cab), but there's no record of that suffix anywhere.
And SXA: SXA is a known suffix, identifying an '84 passenger car 190 hp 305. ...Except this engine is a '73 400 out of a truck*.
*(Another VIN match, with another "What the...?" recycling example. The engine was pulled with its original heads. Except, the casting number was only ever used on 327s in the '60s. Don't make much sense, does it?
Well... If you go far enough down the rabbit hole, it comes to light that they were only used on 327s in the '60s, except for that one time when GM got retarded and brought that casting back for just three months in 1973, so they could drill steam holes and slap them on 400s going into trucks with manual transmissions. Why? No idea. ...Just another layer of confusion in the cesspool that SBC casting numbers and codes are.)
