Olds Engine Identification

Olds v-8 blocks had their I.D markings on the top front of the block behind the timing cover and infront of the intake. it was a 6 digit number followed by either a letter or a number. the Julian date can be found on a small pad in the casting under the cylinder head at the left front of the block behind the power steering pump, usually caked in shit and so rotted you can only read part of it. this is only somewhat critical for guys doing accurate restorations. cylinder heads had a marking to the lower left of the cylinder head near the left spark plug as you face the head.

i consider there to be two generations of oldsmobile v-8 engines. Prior to 1977, Big Block olds engines used letters on both the block and heads, small blocks used numbers. these were the 330-350 small block engines, 400-425-455 big block engines. there were several variations in both heads and blocks from the mid 60’s through 1976. some are worth big money- some are scrap metal.
Starting in 1977 they abandoned the big blocks all together and redesigned the small block castings and heads. often referred to as smog motors, this generation of engine was the 260-403 engines, including the often seen 307 of the 1980’s. these engines were marked on the block and head with both a number and letter, like a 7a or 5a as an example. it happens frequently that you buy a 350 from a late 70’s car that looks identical to an early 70’s engine and it turns out to be a complete piece a shit for any kind of a serious build platform to start out with over an older engine.

i found a few old I.D charts in my library that should help you guys to reference where to look and what you have when you have an olds V-8 you want to identify. it is by no means completely accurate as over the years many parts were mixed and matched for auto repair and performance, and has been disputed by many olds websites and enthusiasts over the years. you may need to copy it to your computer and blow it up to read it.

olds crankshaftolds blocks
bbo heads
sbo heads

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