Dr Terry will know more about these. But I think you are correct, they were TH400 but also 350ci engines. Remember although it was 1968 it was late in 1968 and the 350 had been around since about August 1966 in SS Camaro and since August 1967 in the ChevyII Nova SS. The 1969 version of the 350 had been in production since the end of July 1968. GMH would have had access to some of these for the upcoming HT although they didn't get their hands on 1969 spec production engines until around March-April 1969, so what was in those HK's may have been 1968 or early 1969 engines. Until I saw one in the flesh I wouldn't know. Unfortunately they were NSW rego I believe so not easy to find their original registration records.

Thank you HK327 and Dr Terry, I have an article written by David Mckay in the Sunday telegraph in July 1971 road testing our HQ Monarols 350 and he mentions the 68 monaros

with the bigger motor's and turbo 400 gearboxes

my 2c .. just quoting publications I have (have read) which might help

John Smailes in his book on the event states that all 3 GTS327 Monaros (no mention of 350s) were fitted with 3 speed autos in place of the usual manual
and the cars were modified for air conditioning. I am pretty certain these would be T400s as my recollection is that the T350 was not released (interestingly a 2 speed
PowerGlide replacement) until 1969. So...
I checked Wiki and it says - The Turbo Hydra-matic 350 was first used in 1969 model cars. It was developed jointly by Buick and Chevrolet to replace the two-speed 'Glide
This is also stated by a number of USA motoring mags- MotorTrend etc

The 'Official racing history of Holden' states that mildly modified 3 GTS327 Monaros were used and ... (bit unhelpful that)

Norm Darwin's excellent book 'Monaro Magic' states that after testing a HK GTS307 coupe (by David McKay) the request was that all the cars to be used
be fitted with the latest 350 V8 engine and a bed in the back !

Yes, I forgot about the "bed" in the back. They removed the rear seat entirely & fitted what looked like a fibreglass moulding resembling a bed, but with good side supports like a racing seat. There was no cushion or trim of any sort, even the carpets were removed leaving a bare metal floor.

Dr Terry

The TH400 is tough as nails, unless you don’t service it you’d never kill one with a 295/300hp 350 unless you were towing with it and letting the converter cook the oil (ie insufficient cooling). In a HK sized vehicle eg ‘69 Camaro, the 300hp 350 when optioned as a turbo-hydro (you could still option Powerglide in 1969) you got a TH350, the TH400 was for big block only. So GMH must have specifically ordered the TH400 to go with the engine - to that stage the only Chevrolet small block fitted with TH400 was the 275hp 327 in B-body (full size). Depending upon when they ordered the engine and box the TH400 was probably the only 3spd auto available anyway.

What I’ve been wondering is, would the engine have been the stock 1968 L48? These were 10.25:1 and needed high octane fuel. When GMH built the VB Rally carbs with XU1 gear they were lower compression than XU1 to be able to use standard grade fuel if needed. And that was for Australian use, the HK’s had to go a lot further afield.

I thought of that for Australia. But what about the other parts of the world like Bulgaria, Turkey, Iran, Afghanistan and India. Surly they didn't freight higher octane fuel around the world? I guess they could have bought it in Italy before heading to Turkey? And then filling up again in Perth? I know our Super fuel was fine for those engines, but our standard and US Regular grade weren't - they were to be run on the higher octane fuel in both countries. The lower compression engines like the L73 327 (aka GTS327) and the LM1 (aka HT-HG GTS350 auto) engines were the engines designed for US regular fuel but our Standard grade fuel here was too low for those so they had to run on Super grade. Finding Super grade across Australia was obviously a worry enough for 1979 with the VB Rally cars, so I can only imagine in 1968 that buying suitable fuel outside of UK, France and Italy might have been a stretch?

I just noticed Jack Murray's entry - HK Belmont Automatic, car 91. You don't find too many of those today! Look at the penalty points on Wiki for them - must have been Jack throwing explosives out the car that cost them!

https://en.wikipedia.org...ydney_Marathon#The_route

Edited by user Wednesday, 18 January 2023 2:58:02 PM(UTC)  | Reason: Not specified