I finally found the proof that I have long suspected. GMH always intended that apart from HT Brougham, V8 GTS and GTS350, if you optioned an L31 engine in HT that it would have retained the standard M15 transmission not get an M21 transmission.

In the HT Engineering Technical Specifications, the PTC pages were originally issued in December 1968. The April 1969 version has a revision designator against blank line in the table against L31. It has 3 rows: blank, M21 and M35. Against L32 it has M15 and which models it was standard in but L31 is blank on that row.

However I just found the revision letter for that April 1969 page and other pages revised at the same time. It says "3-speed manual trans. deleted from 308 HC V8".

This explains why the HT V8 M15 is a stronger gearbox than the standard one in all other series and HT 6cyl models. It was always intended for a higher torque engine. It also explains why L31 M21 is a very rare combination in HT-HG outside of V8 GTS - the use of the imported M21 transmission and shifter made the PTC far more costly than it would in HQ-HZ with the locally made Aussie 4spd. L31 M35 later L31 M40 in HT-HG was far more common as both that 6cyl Powerglide adapted to suit a 253/308 and the Trimatic were produced locally.

Edited by user Friday, 10 February 2023 8:21:30 AM(UTC)  | Reason: Not specified

If he ordered it (as in retail order) it probably took the correct amount of time as it would have been a build from scratch car. Plenty of people thought they "ordered" a car but really all they did is bought a stock order vehicle off the schedule. But an L31 HT ute would never have been a stock order vehicle, especially if he also optioned N10. Was it a Belmont or Kingswood? L31 in my experience was far more commonly optioned in HT on V8 Kingswood rather than V8 Belmont in Ute, Wagon and Sedan, and almost all times you find it, it was also optioned with an automatic transmission as the standard M21 had the extra expense of a Salisbury rear axle whereas L31 M35/M20 retained a banjo albeit the added expense of LSD. Note he never actually "ordered" L31 M21, he just ordered L31 over the standard L32 and M21 came with it unless auto otherwise optioned. If he'd left the car with the standard L32 then he could have ordered M21 as L32 came standard with M15.

I can't find the HT pricing at the moment but here is HK on July 30 1968 (inc 15% sales tax):

HK Belmont ute: $1576.28
HK Kingswood ute: $1637.85

Add:

V8 auto (L30 M35) with G92 (2.78) or G93 (3.08) and G80 (LSD): $477.79
V8 manual (L30 M21) with M11 (console), G88 (3.36 LSD) or G89 (3.55 LSD) or G94 (3.08 LSD): $548.05

The imported V8 M35 was slightly dearer than the Saginaw 4spd but the 4spd came with console worth about $18. In HT-HG the 253/308 Powerglide would have cost GMH less as those used the locally assembled 6cyl Powerglide whereas the one used behind 307/350 were fully imported.


Funny though they'd tell him it was a "GTS ute" because it had quad outlets! All HK-HG GTS or V8 GTS were single exhaust unless ordered otherwise (which was rare as it would have meant a wait like ol'man Simmons with his HT ute). The only HK-HG that were standard with N10 were GTS327 and GTS350. It remained this way until the start of HX.

Edited by user Saturday, 11 February 2023 9:33:11 AM(UTC)  | Reason: Not specified

If he bought a standard HT V8 Kingswood ute he could have had a 253 with a decent gearbox, the M15 3spd, those were tough as nails. It would have been a better load carrier as reverse was 3.59:1 vs the Saginaw's 2.54:1. 1st gear was 2.48:1 though and would have come with a 3.08 banjo so 1st gear wouldn't have been as nice as the M21 Saginaw which was 2.54:1 with most likely a 3.36 Salisbury rear axle although if he ordered it, it could also have been 3.08 or 3.55.