In 1984 Group A racing was introduced to Mt Panorama sponsored as the James Hardie 1000. This also spelt the end to Group C racing with big flares, airdams & spoilers. Although the group A cars were not outright contenders for the Bathurst title they did run in a class of their own. In 1985 the group A cars started from the front of the grid spelling an end to the Nissan Bluebirds, Mazda RX 7s and Chevrolet Camaros. They were however replaced with a new breed of Jaguars, BMWs, & volvos. In 1986 the last of the front running VKs were run at Bathurst with Allan Grice taking the win in a VK commodore. 1986 was sadly very memorable with Mike Burgmann hitting the Bridgestone bridge on conrod straight and was killed. This was the reason for introducing Caltex chase to lower the amount of time cars spent at high speed, it also saw the introduction of the 161 lap Bathurst race.

The 2 Marlboro HDT cars finished 1-2 On the last lap Brock slowed allowing David parsons to catch up to grab the opportunity to pass the chequered flag together giving Fans, HDT & Holden a long-awaited 1 - 2 form finish with Brock & Perkins leading.

6th Year model
D - 1984
E - 1985
F - 1986

7th & 8th - Assembly plant
J6 - Australian Assembly plant
H1 to H4 - Brisbane
H5 to H9 - Sydney
J1 to J9 - Melbourne
L1 to L9 - Adelaide
Z1 to Z9 - New Zealand

9th to 13th Serial Number
Sequential Production number, This designated the serial unit number at each production plant starting at 00001 and continues in numerical sequence regardless of vehicle type.

14th - Series Code
K - GMH Model identification as in VK

Body Number
Reference number followed by Assembly play suffix
A - Adelaide
B - Brisbane
M - Melbourne
S - Sydney
NZ - New Zealand

Trim
Interior Paint and  Trim colour combinations

Paint
Exterior All over or Lower Colour

Top
Exterior - Upper body selection or roof colour

Build - Month and Year
Date of manufacture by calendar month and year in which the body shell and power train are conjoined and the vehicle is driven or moved from the production line

Production Option Codes
Including Power train (Engine, Gearbox and Rear axel)
Identification option code are only used when components differ from those allocated as standard to a particular model

6 - requirement in event of second or further serial number duplication

 M21 in High performance V8s

1st - 2.54
2nd - 1.83
3rd - 1.38
4th - 1.00

REV - 2.54

M20/M21 Aussie 4 speed 1.9L of Oil

Takes 1.6L of Oil

Refill (approx) 2.3
Dry 6cyl - 6.1
Dry 8cyl - 8.7