..Here is a purists view from back in the mid 1970's.... I was only a kid then, but I listened to all of the guff that was discussed from these fellas when so many stories abounded about the inherent values (or lack of) of the big 3 models that a young blade might buy for bragging rights to show off to his mates.

...the HK GTS327 was considered to be a monster with heavy clutch, terribly harsh ride and heavy steering. The HT GTS350 was seen as being a nothing model and no-one really wanted them. The HG GTS350 was seen to be the banger to aspire to....the most potent and powerful of the three.

...this is purely the view of a bunch of knockabout mechanics working for dealers in the prevailing period....not a retrospective on their relative merits today. I had the opportunity to buy a 4 speed HT GTS350 with the braided weave vinyl interior...I knocked it back for a more attractive HQ GTS350 Coupe with Houndstooth trim in 1979.

...this is also not a personal dissertation...it is just what the thinking of pub brawlers and greasy faced blokes were discussing at the time in the mid/late 1970's....and let's face it...their conclusions was as good as gospel gleaned from all their bosses and service managers way back then.

Edited by user Saturday, 20 August 2016 9:35:10 PM(UTC)  | Reason: grammar and continuity

Nick,
Best current estimates for HT GTS350 production are between 700 to 750, including exports. I believed the lower number for a long time, and I believe Byron has checked with Ben Stewart, who believes the higher number to be closer.
Of these, around a third would be 350 Autos.

The changes for the HT GTS 350 are not as many as you might think, and not as extreme and "all out" as the GT HO.

The front and rear springs, shock absorbers and front stabiliser bar are carried over from the HK GTS327, the only appreciable change is that which covers the entire HT range; the adoption of rubber cored front upper and lower suspension bushes vs the solid bushes of the HK. The upper wishbone attachment point was altered during early HT production, and at least some of the HDT Monaros had this modification. The suspension for HK 327 was set up by Bob Watson in 1968, and the fact that it remained unaltered to the end of HG production is an endorsement of the job he did.

You have touched on the brake vents, which come in many versions. Some HT GTS 350 do not have them at all. The methods varied as many were done as a service item by dealers using whatever tools came to hand, such as a jigsaw to cut the vent with the cut panel bent up. There is also a punched fully flanged factory version of the vent, which I've seen on export cars.
The brakes were also improved with the addition of a thicker front disc for 350 only, and a matching caliper. (this modification became standard on all HG models), and a higher reservoir capacity brake master cylinder for HT GTS350 only.
A vented splash pan also existed as a concept and a part number, but to date none that I know of have surfaced.

I don't want to turn this into a "how to fake a HT GTS 350 cookbook", but in addition there were throttle linkage geometry changes, alternator pulley changes, tailshaft changes, gearbox bearing upgrades and many other small alterations.

The engine for the manual cars was a standard US L48 300HP 350, although that engine could come from a number of plants in the US.
There has been discussion here regarding optional heads (186 castings, vs the standard 041), camshaft and different engines for some of the factory cars used at Bathurst. I haven't personally seen proof of any of this, but I'm fairly sure the camshaft remained unchanged. I know at least some of the cars had 186 casting heads as supplied from the factory.

I agree that up until recently the HK327 seemed to attract a higher price, which makes little sense given quite a few more of them survive than HT GTS350, but then the "value" often doesn't follow any rational rules.
HT and HG GTS350 prices seem to have risen quite sharply recently, although so few change hands publicly that a real trend is difficult to determine.

To reiterate, estimates are:

HK GTS 327 production: 1192, surviving cars: 200-225*
HT GTS350 production: 700-750, surviving cars: 175 max.*
HG GTS350 production: 400, surviving cars: 100 max.*


*Note. The "surviving cars" number includes partial survivors, ie Firewall number, ID plates etc. The real number of complete cars will be a fair bit less.

Regards,

Geoff

Geoff has already given the numbers. About 125 auto HT GTS350.

The reason Nick for the extra HK GTS327's is a good one, GMH never intended to build that many. I'll tell you one day why there were so many.

The HK GTS327 is held in high esteem for two reasons. Firstly the Holden coupe is the reason Ford built the XR GT. Their moles/spies found out and Ford beat GMH to the punch. GMH had never intended the HK GTS327 for Series Production, just for the ATCC or Improved Production with Norm Beechey. It was Ford's win in 1967 at the Gallagher 500 that changed their minds, and thus the suspension of the car was tuned as one of the last things done to the car with that in mind. Secondly the HK GTS327's easy win in 1968 was the reason Ford created the GT-HO, without the GTS327's win at Bathurst there would be no GT-HO.

The HT GTS350 i'll go into later, have to run.

The HT GTS350 wasn't improved over the HK to keep up with what Ford were doing, it was a simple evolution of HK GTS327. The HT GTS350 was signed and sealed ready to go before the HK coupe was even released to the public. It simply got the standard 350ci 4BBL engine, the L48 as this was the only 350ci Chev engine available in 1967 and 1968. The LM1 engine in the HT 350 auto wasn't released in US vehicles until 1969 model year and the auto option was a late thing in HT evolution, thus the GTS350 got the 1969 spec L48 (300hp rather than 295hp for 1967 and 1968). The HT GTS350 manual is a special car, more special that many know (again this is not my story to tell). The fact it was allowed to be designed in 1967 and early 1968 with the L48 engine gives a glimpse of this - the L48 was essentially exclusive to Camaro up until this time. GM heavies including the GM Bill Mitchell were very much interested in what GMH were doing with their new coupe, more than most realise (remember the HT facelift design was done during HK design). Car guys like John Schinella were very much into the success of the car even after John went back to the USA to design cars like the 1977 Transam (Trigger from Smokey and the Bandit).

The reason the HT GTS350M is held in such high regard is as good as the HK GTS327 was, the HT was better. Plus the car won Bathurst again the next year against Ford's no-expenses spared GT-HO road registered race car, no simple feat, and also went on to win another two endurance races after Bathurst (Lakeside 1500 and then the 1970 Rothman's 12 hour at Surfer's Paradise). The 1969 race was faster in lap speed and total race time than 1970 so it is a strong possibility that the HT (or the HG facelift) would also have won in 1970 against the GT-HO II if GMH had continued with the Monaro as Harry Firth wanted them to.

So to many the HK GTS327 and HT GTS350 are very much valued similarly for different reasons. The HG is really no different to the HT, it is simply an unplanned facelift and it is only cosmetic differences. In reality the HT was cut short as the original HQ was scrapped and the new North American sourced HQ design we got was going to be so late that the HT would have run for too long. Those HT GTS350's with the USA engines show you roughly how many more HT GTS350's would have been built if HT ran as long as planned, the Canadian engines in the last of HG are top-ups to see the rest of HG out.

Edited by user Monday, 22 August 2016 4:44:18 AM(UTC)  | Reason: HT info added.

I'll leave that story to be publically told by another.

I've edited my above post to add more re the HT.

...not too sure, but thinking back the HG GTS350 had a more "efficient" Quadrajet carby and a few more tweaks to keep the breed on song ??

...and its always good to get to the bottom of these stories with the likes of the very learned crew on board here...Cheers to them.

Edited by user Monday, 22 August 2016 4:13:18 PM(UTC)  | Reason: Not specified

HT and HG engines are identical, as are their carbies. The only different HG 350ci engine is the Canadian one right at the end, these have a few more Hp due to the heads, but the carbies are the same. HK GTS327 carbs are the same thing too, just an earlier year version.

One of the Bathurst GTS350 got disqualified for bigger valves I believe.

It is priveliged as it is not my research hence not my story to tell.

So the valves were standard size HK, how did they get it wrong.

Oversize valve stems ? one would have to be a moron to claim that as a advantage for any performance advantage.
Much like in sports finding one has smoked dope, it's not an advantage at all but in fact only a disadvantage.