Initially you couldn’t order 5.0L in VC Commodore, only reserved for Police use. HDT had 5.0L engines but these are not Commodores. The main reason was the XT5 4.2L with dual exhaust was more powerful than the XT4 4.2L. That changed later though.

GMH didn’t tool for LHD with the W Holden or Statesman (HQ onwards). The U sized Torana (LH onwards) was built LHD. I don’t think there were any more LHD GMH (later Holden) products built for export until much later. There were LHD V2 and VZ coupes built as LHD Pontiac GTO and I’m pretty sure LWB (Statesman) as well. And the Zeta platform (VE/F) there were plenty.

Edited by user Monday, 4 January 2021 3:46:44 PM(UTC)  | Reason: Not specified

I’ll rephrase it. A VC HDT isn’t a Holden Commodore. You couldn’t walk into a dealer and say “I want one of those with a 5.0L engine, in metallic green and light trim etc”.

On the Commodore logo on it, is it so that a “Commodore” could race in Group C with the V5H engine mods? That is 500 “Commodores” were made with those engine mods. Not sure how homologation worked in 1980. In GroupA the HDT and HSV cars afaik had to be sold and marketed as a GMH/Holden product to recognise the 500 evolution of type vehicles, with (at least in VK) 5000 of the VB prefixed V5H 304ci engines fitted to Holden Commodores prior to the VC prefixed GroupA engines fitted to the blue VK GroupA. Not sure how that worked with VL especially the EFI GroupA.

I found the VK-VL GroupA FIA homologation. All 115 pages of it! Looks at first glance it worked something like L34, where GMH used the base SL/R, updated it from LH L34 into LX L34 and then used A9X to further modify the L34 homologation.

https://historicdb.fia.c..._number_5282_group_a.pdf

well... actually in my opinion (and remember I helped set up the whole shooting match up in the first place) a VC HDT is a Commodore, it was made in a GMH VAP (Dandenong) with a GMH car line code and model designation.
It was not sold to HDT in North Melbourne... it went via them for further modifications before delivery to a dealer (all VC HDT orders needed a dealer code.. even internal orders). They had the original engine retained as fitted in the plant
(HDT were NOT allowed to change entire engine only engineering approved parts)

Given that VB Holden was already homologated... why build VC HDTs? Ostensibly for two reasons only... to give the Commodore a marketing kick along by adding a sporting flavour on a limited edition model
(remember that VB only had the SL/E 8VX69 308 pack with 5litre/4 speed as the only decent sporting performance version despite the squillion VB 'Sports pack across 'L'and 'SL' models))
AND
this is the important bit... to give HDT funds... dollars $$$$$. HDT made lots of money making VCs. It was an indirect way for dealers to pay for the Holden Dealer Team racing efforts. Dealers paid GMH for the 'base' car
and HDT for the modifications. Simple arrangement... designed NOT to upset GM Detroit

But.. and this is where things started to unwind, Milamunda Racing (aka HDT racing team) decided they would use the large valve heads and better inlet manifold from the road cars on VC race cars
(VB racers used SMALL valve heads as CAMS had outlawed L34 style engines as used on A9X) as they were getting a pasting from Johnson and other Falcon competitors

Oooop.... NOT homologated ! and Brock was excluded from race results as post-race scrutiny picked up the invalid race engines.

Brock WAS allowed to continue racing with big valve headed engines as long as he fitted all the SL/e fruit salad to race cars (he ended up with aircon evaporators taped to the passenger floor for example)
and PGB was NOT happy...it went all the way to the Vic Supreme Court. No winners in that....(do a Google the whole thing is VERY long!!!)

but ah ha... VH is now released. We now have an Holden built Commodore SS model with NO frills.. with 5 lite engine with V5H options (BIG valve heads, good inlet manifold) and this gets homologated . Woot!Light weight car
with good engine .. but note still a 308 (as Group C rules rules said std size street engine and CAMS set weights for all brands of race cars). These rules stayed thru to the day-glo VKs that came 1-2 at Bathurst
The last hurrah for Group C big bangers.

Next ? comes Group A rules... based on engine size. The hurdle was the 5 litre rule. cars with L31 engines 5044cc were 75 kg heavier than cars with LV2 4987cc engines. and under Grp A rules, a manufacturer had to make a minimum
of 500 examples of either (how we got the Blue Meanie) with another 5000 made in the same carline with the same drive train. GMH made 5,000 Sl sedans, Berlinas and Calais with 4.9litre LV2 engines and V7X mods (being the famous
'5955' improved inlet manifold and of course 'B'cast big valve heads) I had a 234 pack Berlina sedan.. level 2 Berlina level 3 engine LV2 with V7X and 4 speed (M21) gearbox as a GMH co car (which i later bought as I left Holden)

Edited by user Monday, 4 January 2021 9:21:14 PM(UTC)  | Reason: Not specified

Pretty good precis Smitty2.

Dr Terry

Edited by user Tuesday, 5 January 2021 6:38:15 AM(UTC)  | Reason: Bloody auto correct spelling !!

1985 - Under Group A rules Australian manufactured cars recognised by CAMS as Group A - 5000 cars to recognise the body coachwork/silhouette (length, height width etc) regardless of the mechanical specification.
1000 cars to recognise the mechanical package.

Edited by user Tuesday, 5 January 2021 8:13:40 AM(UTC)  | Reason: Not specified

I totally agree, how about the single timing chain BS f me dead the bastards had the double row gears for f sake. who puts a single row chain on when replacing them, no one but some moron in Holden's bean counters came up with saving 2cents each engine.

Look at the VB race engine, I have 331hp and the blue VC is 391hp AT 6500RPM with L34 valves and 10.5:1 compression ? how with stock pistons, don't think that they could use the L34 pistons in the VB-VC.

Dickie boy's 5.8L 2V heads XD 410hp at 6500 and the XE 437hp at 7500rpm

Camaro 5.7L at 480hp how so, must have better heads than the stock 5.7L Camaro of the time that was a slug in the USA. it was a s box leaf sprung rear drum brake crap. I am sure dickie boy had rear disk ?

Can we find out now what spec engine they were running exactly nowadays ? A 308 even with 330hp for a stock valved un ported head sounds a bit high to me as most worked street 308 only had 330hp with L34 valves and some port work.

That RX7 and others were a joke because we could not buy them types off the floor here.

Look at the turbo 6 Nissan ha ! we could not get them, were they the same 3.0L 6 as the VL Commodore ? if so we could of ran a Turbo 6 Commodore.

I would of bought the VL turbo any day over the VL V8 crap, and the EFI 5.0L only came out near the end of the VL and at that price forget it, my boss bought one and had it re painted directly.

The Camaro was a new 1978 Z28 but CAMS made them run 1974 sheetmetal. It only ran drums early on due to CAMS buggering them around. The Camaro was standard with drums but discs were optional, and in 1981 they ran rear discs.

Whilst the later Z28 weren’t power houses on the road, the engine basics were the same as a 1970 Z28 which was a 370hp engine. It was just pollutioned up and dumbed down for the street and for ULP, but the car was already homologated with good parts under international Group1. Plus KB had been running big horsepower SBC’s in F5000 so they knew the engines well. Given GroupC allowed free choice of certain bits like camshaft, carb etc I’m not surprised the got 480hp. I’d have to search harder but I bet that Group1 homologation included high top pistons, tube headers etc.

V8 VL is the only VL I would have had, and then only a Calais not a Commodore as I hate the look of VL Commodore. VL V8 was a good engine, just low compression. They had big valve heads, just needed the manifold modified or replaced with a HDT style one and unfortunately pistons replaced to get them back up to over 9:1 compression. Only Trimatic though, however not that hard to change to a 5spd manual. None of which you’d have probably bothered with in the early 90’s as a VL GroupA (red one) were cheap back then as a used car. Or you’d buy a good VL V8 and a VN wreck and swap the engine and box over, very easy conversion.

that is incorrect.....
CAMS outlawed the big valve L34 engine ....as it also did re rear disk brakes on Toranas (I kid you not) when the Commodore was presented as the car to replace the A9X
(and at the same time the XD taxi for the XC Coupes) complete set of NEW rules...

any reading of the history of tin top racing in Australia gives full and better details of this