Need help decoding a 455

[humblemunkey]

My dad has a engine that we think is a buick 455 but not sure if its a pontiac or olds.
The numbers stamped on it are

1241735
45H420018

There is also a 75 stamped on the block. So, im guessing its a 1975 block?
We want to know what stage the motor is and hopefully what the engine came out of.
Thanks!

 

[bob k. mando]

differentiating Buick, Olds or Pontiac ( BOP ) is easy-peasy.

http://www.teambuick.com/reference/ident_eng_visual.php




4 5 H 420018
4 = Buick
5 = 1975
H = Flint, MI production plant
420018 = sequential production number, matches the last 6 digits of the VIN from the car it came from. not very useful if you don't already know the car.

Buick only made 2 v8s in 1975, the sbb 350 ( 6 bolts in valve covers, VERY different than sbc 350 ) and bbb 455 ( 5 bolt valve covers ).

 

[Buford26]

Flint built B, C and E body cars used 4000001 to 562405 in 1975 for the sequential number range, so the engine is from a LeSabre, Estate Wagon, Riviera, or an Electra 225. The last year for the Stage 1 455 was 1974, so that doesn't apply to 1975 and 1976 (last year for 455).