Holden HK to WB Engine Numbers

Engine Numbers

The are several numbers stamped or cast on a block that identify the capacity of the motor and the vehicle it was installed in.

Prefix:

This refers to the identification of the engine. For a variety of reasons, engines need to be correctly identified, and it is this prefix which clarifies areas such as capacity, compression ratio, transmission, etc. The location of the engine number prefix varies depending on the type of engine.

• On all L6 (in-line 6 cylinder) engines, the prefix can be found stamped on a pad on the right (viewed from the rear) side of the engine block above the engine mount
  boss.
• On 307, 327 and 350 cubic inch VB engines, it is located on a pad in front of the right (viewed from the rear) side cylinder head on the block.
• On 253, 308, 4.2 litre and 5.0 litre VB engines, the prefix is stamped on a pad above the engine mounting on the left (viewed from the rear) side of the block.

Block:

Each engine block has a casting number integral with metal castings for identification purposes. The block casting number can tell you important things likestandard bore diameter & stroke length, performance characteristics, and in the case of a Chevrolet V8 block, the crankshaft journal size and very often but not always the type of main bearing caps (ie two or four bolt).

• On all L6 engines, the casting number is located on the left (viewed from the rear) side of the block, just forward of the engine mounting boss
• On all 307,327 and 350 cubic inch engines, it is located on the left (viewed from the rear) top rear surface of the block near the bell housing attachment.
• On 253, 308, 4.2 litre and 5.0 litre V8 engines it is located on the left (viewed from the rear) side of the block slightly above and forward of the starter motor mounting pad.

Head:

• All L6 cylinder heads can be identified with the engine complete. The casting number is to be found on the top left (viewed from the rear) side toward the front of the engine. A locationg ear on the rocker cover gasket will need to be removed to expose the full casting number.
• All V8 engines require the rocker covers to be removed to expose the number.

Abbreviations:

Most of these require no further explanation, however lu=limited use and uu=uncertain usage do. These terms are limited to the HK, HT, HG and HQ models. The rules of Series Production racing in the 1960s demanded that vehicles involved in this motor sport had to compete in showroom stock condition. This was the sale reason why Model Number 81837 was created. This vehicle enabled GMH to successfully compete in motor sport despite the parent company world-wide ban on motor sport involvement

lu=limited use - means exactly what it says. Certain parts used in the manufacture of cars were available 'officially' for very short periods of time. This satisfied the rules and as a result, these effectively 'modified' vehicles were eligible for competition.

uu=uncertain usage - is a term used where no one, not even GMH can completely clarify the correct usage of these parts, Vehicles exist in original condition with these variations, and documentation exists to support this, sometimes only in very sketchy form.