92 replies to this topic

[Shiney005]

I tried doing some homework on that a while ago Dave. The first parts book (Feb 1974) only records one camshaft for both 308 and 253. The first amendment sheets in Feb 1975 show a different cam sprocket for L34. The 308 cam retarded by a few degrees would have a similar effect as using a cam with flatter profiles. (These sheets also amend parts that never made it to production but were entered in the first parts book. i.e. the XU2 ashtray) Once you get to the Sept 1975 book, they are showing the differing part numbers for 253 and 308, as well as showing the cam for L34 as the same as 253.

The October 1975 amendment sheets don't mention any cam.

Either way, GMH wanted the L34 drastically de-tuned to keep the media at bay.

[yel327]

Guys, once a month or so I look in here to see if there was anything of interest to see. This is the fist time in a long time I thought it was worth posting something.

 

The XY GT-HO fable is exactly that. A Chinese whisper, perpetuated over time. The original quote was:

 

"..On a dollar for dollar basis it is probably the best performing four-door car in the world...". Evan Green, Sun Herald 22/8/71.

 

As Dr Terry has already said, the Mercedes is quicker. But there were also 4 door sedan Dodge Coronets in 1969 with 426 Street hemi engines. These would easily kick a Phase III's arse in 1/4 mile and top speed, and they were autos.

 

Sure a GT-HO was a quick car in any of the three forms, the Phase IV if produced may have been faster in top speed due to the body shape, but from what I have read they were to get a less powerful engine due to a smaller cam. But the reality is the HG GTS350 manual (which co-incidentally only ever overlapped the XW PhaseII by a mere few months in availability, ie it was gone from production before the end of 1970) was only fractionally slower than a standard XY PhaseIII in both 1/4 mile and top speed. This is with a production, hydraulic cammed 350, in fact the lowest power 4BBL 350 available in the USA. The Cleveland in the PhaseIII were hand built solid cam engines. But they did essentially the same things time-wise but in different ways, the Falcon was brutal, the GTS350 far better mannered. If GMH had built Old Man Emu, a HT GTS350 with an LT1 engine (plus M22 and 12-bolt) it would have been a brutal car too but Ford would have had its tail between its legs.

 

You have to remember, Ford were allowed to race. They had a massive budget and win at all costs was applied. This is why the GT-HO's were so blatant and brutal. GMH were not allowed to race, GM had had a corporate ban since 1963. Everything had to be hidden, no race cars allowed to be built and no Company involvement. This is why we had the HDRT and HDT. It is why GMH hid the performance of all the higher performance cars. Very few road tests ever made the light of day unless they were either hobbled cars or heavily supervised. At the press test days for the HK GTS327 (Lang Lang in early July 1968 and at Surfers Paradise later in July 1968) there was a GMH staffer in every GTS327 test. The Journos were not allow the cars to rev past the tacho redline, which was the 186S redline of 5500rpm. There was no 307 manual present to compare with, only auto cars with tall axles and aircon. This behaviour continued right up into HJ when the new more powerful 308 was released, all GMH supplied road tests cars were hobbled in some way, almost all 308 Holdens had single exhaust. Very few proper road tests were done on properly tuned cars. Rob Luck got to test a HK GTS327 in proper tune, and Dave Bennet's GTS327 was also tested, these were cars in proper tune. Mel Nichols lucked a GTS350 manual in proper tune and Peter Robinson wouldn't believe him, but managed to drive a later HG GTS350M in early 1971 and apologised to Mel as he then realised how good the car really was, even thought it set a new benchmark. There were a few other reports done where the Journos were shocked compared to the official Press Test cars, there was one on an early LX SS 5.0L where they timed it and started to look back at the old Muscle Cars to find something as quick.

 

The SLR5000 with L34 was not meant to be a quick 1/4 mile road car. They were hidden from Press and hard to buy. Cam and Carbs plus exhaust after the first joint were free in GroupC, hence why they got the standard HT-HQ cam timing (retarded 253 cam) and a standard HQ Quadrajet just converted to manual choke due to the lack of exhaust manifolds. They only got what was needed to race that couldn't be changed like the modified heads and intake manifold plus dizzy. Nothing they got would have made them much quicker over the quarter than a stock SLR5000, and in fact the taller tyres probably gave them an effective rear axle ratio of about 2.5:1 down from the 2.78 of the stock SLR5000 would have slowed it down compared to the 13" tyres. Sure the L34 engine had a point of compression higher than a stock 308 and bigger valves and exhaust headers but the cam remained the same and they still had the peashooter tailpipes so the gains would be nowhere near as good as would be with a bigger cam and exhaust. All you have to do is look at the HQ 308 vs the HJ 5.0L (LH 5.0L changed at the same time), the new cam and smaller dish on the pistons saw the engine go from 226hp (real GMH dyno figure) to 250hp SAE Gross. 24hp is a fair difference. The new cam was basically the same grind as the Chevrolet GP hydraulic cam as used in HK-Q 307/32/350 engines and the compression went from 9.0:1 to 9.7:1. So imagine what the L34 might have been like even if all they did was fit the upcoming HJ 5.0L cam and fit 2" or even 1 7/8" tailpipes like the Holden dual tailpipes. You'd imagine on an engine dyno with the better heads, the opened up intake manifold and the exhaust headers that the standard L34 engine would have produced closer to 275hp or thereabouts on the same dyno that saw the stock HQ at 226hp and stock HJ at 250hp, and the L34 with the HJ 5.0L cam should have got closer to 290hp. Norm Darwin published Redco dyno plots in Torana Tough, on the Redco dyno the stock HQ 308 got 190hp and the stock L34 260hp.  But GMH had no need to anything more than they did with the L34 engine, the car was a means to an end and they didn't want it to appear like a road rocket - remember the supercar scare was less than 2 years ago.

 

My vote on the quickest 1/4 mile bog standard production carbied GMH vehicles would be the final HG GTS350M (with Canadian 350), VK Group A, early LX SS 5.0L manual and maybe throw an L34 with a 3.08 rear axle in there too. The fastest Aussie built cars of the same criteria would have to also include GT-HO and E49. Not sure how quick the big engined AMI built cars were either, there was a 315hp 390ci engine available in these.   

[Shiney005]

Oh, it's like a warm pair of Ugg boots on a cold night.  You have been sorely missed around here Yel.

[Ice]

Wow you are alive good to see you post Byron you have been missed
How about popping in more often and the other place to you know the one
cheers for your input

[Rainman]

That is some great info Yel327. I was excited and hanging off every word. Thanks for dropping in.

[Dr Terry]

Hey yel327 good to hear from you. I have one test on a LH SLR5000 it is a Orange one and on the cover and it ran a 14.9 on the quarter and to 210 top speed. Then ever 5000 after that on ran 15.5 to 15.8 with a 200ish top speed. I wonder if the first 1 was to fast? I have also been in a standard 2 month 76 LX 5000 and it felt a easy 15 second car with 4 blokes in it, easy gear changes and not ringing it's neck so I would say 2 up giving it a hiding it had a 14 in it,cheers Aaron

It should be the other way around. To my way of thinking the later LH SLR/5000 (built after HJ intro) with the higher output motor (advanced camshaft & higher CR) in theory it would be quicker & faster.

 

Then the early LX SLR/5000s (pre-ADR27A) with their standard dual exhaust would be quicker yet again.

 

Dr Terry

[yel327]

I would still bank on the phase 3 or even 2 being the fastest production 4 door sedan in the world. The 426 Coronet would be a rival for sure but they only sold 2 and I would think that they would Weight a little more then the Falcon. Even though they had more HP and Torque under rated like the HO, they only made 2and they were not a production model and they were made in 66. There were a few American cars that would go close eg big block GM, Ford And Mopars and the E49 VH sedans but nothing that I would bet my life on. Maybe I am just a patriotic Aussie, cheers Aaron.

 

Being the "fastest 4-door sedan" is not really a massive claim. No-one really did this. GMH never built a production HK sedan with a GTS327 engine, or a HT-HG sedan with a GTS350 engine. In the USA in 1966-1969 the Street Hemi was available across the model range as a valid production option on Dodge and Plymouth, the fact only two were made in 1969 doesn't mean they weren't production cars, it just means very few people wanted one. The two 426 street Hemi powered 1969 Coronets were valid production cars as were the 3-4 1966-68 versions, one of them sold recently for over half a million $US. Dodge and Plymouth HAD to offer them in production cars so the engines qualified for race duty, which makes them little different to a GT-HO in that respect. The earlier 1965 versions of 426 Hemi optioned vehicles were proper race engines with 12.5:1 compression, but as far as I am aware no 4 door sedans built with these. The 1966-1969 street Hemi was the same engine but with lower compression of 10.25:1. There are various tests of stock versions of these, below is one from Car and Driver but it is a manual car with 3.54:1 rear axle:

 

0-60mph 5.3s
0-100mph 12.8s
1/4 mile 13.8s @ 104mph
Top speed 130mph

 

From what I've been able to find the auto cars (with 3.23:1 rear axle I believe) were mid 14 second quarters (various sources show 14.2-14.5s) but higher top speed.

 

The most reliable tests of Aussie stuff I have found are as follows.

 

Sports Car World December 1969 tested a properly tuned GT-HO. They did not like the car as a road car, said it was clearly built for one purpose, and you'd be better off with a GT or a GTS350 as both were far better road cars. It gets damn close to the street Hemi Coronet. People will tell you the PhaseII and PhaseIII as standard cars were a lot quicker, but this tells a different story. Also look at the fastest lap, fastest qualifying lap and total race time for 1969 Bathurst vs 1970. The GT-HO was faster in all than the PhaseII and 1969 had a fair few laps of slow speed at the top of the hill after Bill Brown's smash.

 

0-60mph 4.9s
0-100mph 16.7s
1/4 mile 14.8s average, fastest 14.4s.
Top speed 128mph.

 

Wheels October 1971 tested a well tuned PhaseIII.

 

0-60mph 6.4s
0-100mph 15.2s
1/4 mile 14.7s fastest (no trap speed). They got a run of 14.8 and 14.7 quarters once they figured out the way to do it without wheel spin. They also say it was slightly quicker than the PhaseII.
No top speed provided but they extrapolate it would do 144mph if it could run to 6700rpm in top. In theory it should have done 132mph at the 6150rpm rev limit. They do not say it did this though.

 

Wheels December 1970, Mel Nichols got to test a properly tuned HG GTS350. They only got the 0-100mph and top speed tests done, which were published as below. When they got the car same back for a second run to do the acceleration and 1/4 mile times it had been "adjusted" to perform like the earlier press test cars, it would not rev past 5500rpm and back to doing near 20s 0-100mph times.

 

0-100mph 16.3s
Top speed 130mph+

 

AMC magazine tested a 38,000mile untouched HG GTS350 in issue 51. The car was properly tuned and tested just like the original tests (full tank of fuel, two people and throttle lift shifts).

 

0-60mph 7.0s
0-100mph 15.95s
1/4 mile 14.78s @ 95mph
No top speed recorded.

 

Racing car news, September 1968 tested a private, properly tuned standard GTS327 (with 3.36 rear axle). He saw through the Surfers Paradise Press drive cover up of the car's true performance so got a private car to test.

 

0-100mph 19.8s
1/4 mile 15.4s (best) @92mph.
Top speed 128.5mph.

 

The SLR5000 and SS 5.0L tests are hard to find, and as I said they had tiny little 1 5/8" tailpipes which if you work out the total X-section are only marginally better for the pair than a single 2" tailpipe on a standard Holden (2 x 1 5/8" pipes have 2 x 2.074sq inch, single 2" pipe has 3.142sq inch). The first thing anyone did back then was replace the 1 7/8" mufflers and on a Torana put 2" tailpipes on. So even with the 250hp HJ 308 they were still restricted, and throw in a 2.78 rear axle (whereas a Holden with 5.0L manual and M21 4spd got a 3.36 rear axle and 14" tyres) and the Torana was hampered a bit even though it was lighter. Plus most LH tests are the early cars with the less powerful HQ engine.
Peter Robinson does give some insight in Wheels in July 1976, where they test a 5.0L manual SS. They manage as below. What the article does say though is "GMH's 5.0L V8 has enough power to give SS more performance than and other locally built car. In fact, it's so strong our performance figures had us comparing them to the old muscle cars".

 

0-90km/h 6.6s
0-110km/h 8.8s
0-150km/h 16.8s
1/4 mile 15.6s (fastest), 15.7 average
Top speed 188km/h.

 

I suspect that if this LX SS had been optioned with a 3.08 rear axle that it would probably get close to matching Rob Luck's GTS327 test, or going even better. Certainly if the tailpipes were modded as described above. However that is the case with any of them, option a PhaseIII w with a 3.5 rear axle or a GTS350 with 3.55 or 3.73 rear end and they'd go even better again.

 

In the end the Mercedes 300 SEL 6.3L was probably faster than any of these bar the Coronets, see link where there are some 1968 press tests quoted: https://en.wikipedia...enz_300_SEL_6.3

 

And certainly the 1975 450SEL 6.9L with its factory rated top speed of 140mph trumps them all again, see here: https://en.wikipedia...Benz_450SEL_6.9

[Ice]

See this is why you need to be on here
Great read Yel

[RallyRed]

Stop it Byron....there's Ford blokes all over the country who are in the fetal position....their only claim to greatness has been debunked!! lol

[S pack]

Stop it Byron....there's Ford blokes all over the country who are in the fetal position....their only claim to greatness has been debunked!! lol

Hahaha yeah. Good mate of mine is a Ford man.

He also keeps telling me the ONLY reason Brocky won in '72 was because of the rain. There's more to motor racing than just being fast in a straight line.

[Rainman]

Such a wealth of knowledge Yel327. Thank you for sharing.

 

Dave, wasn't it 3/4 down conrod before the ford would catch the xu1 ?

 

What about the 70s Porsch/Lambo ect ? thought they would be winding up around the mark ?

[Ice]

Such a wealth of knowledge Yel327. Thank you for sharing.
 
Dave, wasn't it 3/4 down conrod before the ford would catch the xu1 ?
 
What about the 70s Porsch/Lambo ect ? thought they would be winding up around the mark ?

They are 2 doors Ray

[Dr Terry]

Hey DR Terry, I would agree but from the tests I have seen I wonder if the first test of the first LH 5000 was to fast so they slowed down the press cars after that. Surly someone else has the Magazine I am talking about. I have It here somewhere but can't find it.

I don't think it was just the press cars, but from my experience tuning Holdens in the 70s, most (probably art least 70% of the cars I worked didn't have the Q-Jet secondaries opening fully.

 

Many cars were just operating on their primaries & because so many guys drove then in to work in day-to-day traffic, many owners never noticed.

 

New spark plugs & points, set the timing adjust the cry & linkage to get the secondaries working properly & it was a very different animal.

 

I remember a stock 350 TH400 2-door HQ Monaro at a Castlereagh street meeting once. He was doing 15.5s all night, which is around the same as the motoring magazines were achieving. I had a quick look, set the timing to stock & found the secondaries only opening half way. I adjusted his carby linkage according & sent him out again. He went 14.7 & broke out. He was so excited about the sub-15 ET that the break out loss didn't upset him so much.

 

Dr Terry

[yel327]

Stop it Byron....there's Ford blokes all over the country who are in the fetal position....their only claim to greatness has been debunked!! lol

 

This isn't meant to be a Ford bashing exercise. Just making sure that history is correct and not clouded by Chinese whispers over time. GMH did a great job of hiding the potential of the faster Press Test cars and the misinformation is still around today. The GT-HO's were fantastically powerful brutish cars, and are rightfully recognised today for what they were. Ford had no need to hide them. However the fastest Holdens were hidden in plain sight except for people who owned them knew the truth. I doubt many people around today ever drove a bog standard GT-HO or HG GTS350M. Even from near new most got modified slightly, all it took was minor mods and they were way faster than standard. Dave Bennett dynoed his HK GTS327 to tune it properly and when it was a week old he ran it at Calder with the stock D70 tyres, but dropped the exhaust system. It ran 14.46 with only Dave in it and not much fuel.

[Swarbs]

Welcome back Byron 

Don't be a stranger - great read once again

[yel327]

Such a wealth of knowledge Yel327. Thank you for sharing.

 

Dave, wasn't it 3/4 down conrod before the ford would catch the xu1 ?

 

What about the 70s Porsch/Lambo ect ? thought they would be winding up around the mark ?

 

The XU1 was never going to beat a GT-HO in pace on a track like Mount Panorama. The XU1's edge was how much fewer pit stops were required and how light it was hence good on tyres. As it was in 1970 Don Holland was not far behind the two GT-HO's. The records show he was a lap down but that has long since been recognised as another ADRC lap miscount. He was about 1/3 of a lap behind two failing GT-HO's at the end of the race. 1972 was won by an LJ as we know, but had it been XA GT-HO vs V8 XU1 as planned, I doubt the XA would have gotten close. But we'll never know. The only evidence we have is the HDT LC XU1 with a stock 308 lapping Mount Panorama at Easter 1972 up to 6 seconds faster than the HDT 1972 Series Production XU1's. Sure the XA GT-HO would have been better at speed than the XY due to a more advantageous body shape but in reality they are essentially the same chassis and same driveline. Who knows, the V8's may have pushed each other too hard and one of the E49's that finished 3rd and 4th would have won?  

[308 Sunbird]

Very interesting reading thanks to all.

[rexy]

I nearly bought a Chevelle in the classic red and black back in the mid noughties.
Hot big block, turbo 400 and 12 bolt.

The price was right.
Kinda wish I had....

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[Shiney005]

Hey DR Terry, I would agree but from the tests I have seen I wonder if the first test of the first LH 5000 was to fast so they slowed down the press cars after that. Surly someone else has the Magazine I am talking about. I have It here somewhere but can't find it.

If you knew how many magazines I had in my shed, you would understand why it took so long to find this.  I have all of the old magazines from the 70's, and I must concur with Aaron, in that after the first SL/R 5000 test, that particular Safron Orange test car was never seen again. The plates were later fitted to a Chrome Yellow 4.2 SL/R press car. The big difference with the original car was that it had a 3.08 diff in it, where all other press cars were 2.78.  It was the same with the L34's. Only cars with the the 2.78 were tested, not any of the 102 fitted with the 3.08 diff. If one with a H.O. kit was tested it would have been the supercar scare all over again, especially if it still had the Goodyear Grand Rally's fitted.

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7000 RPM with ease?? I think the cam would have put a stop to that.

 

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[yel327]

Very cool, I had seen that test years ago but couldn't remember where. I wonder if it also had a different exhaust to the standard dual 1 5/8"? The fact they talk about it makes me wonder. Shows you the difference the gearing made too. They even talk about expecting it to be de-tuned! So think of this car with the lower powered 9:1 308 and retarded 253 cam. Then think about a post HJ release example with the same 3.08 rear axle and an extra 24hp. It has to be faster than this. Just remember though that the PhaseIII was optional with 3.5 and 3.9 plus the GTS350 was optional with 3.55, 3.73, 4.1, 4.56 and 4.88 rear ends (the last 4 by special order), so that has to be considered into any comparisons.

 

I wouldn't factor the HO kits in Laurie as GMH never built L34's that way. They were certainly far more powerful with one fitted though.