18 replies to this topic

[S pack]

Thumbing through some of my Torana collection the other day looking for something else when I noticed in the LC Torana XU1 Parts Catalogue Supplement there is mention of a close ratio OPEL 4 spd gearbox Pt No. 287649.

Now this is not the normal gearbox ratios fitted to the LC GTR XU1. This would have to be the rarest manual transmission that GMH has ever offered as an option.

 XU1 Opel 4spd C.R G.box.JPG   143.58K   3 downloads

 

According to the October 1971 LC Parts Catalogue this transmission was only available in production against a special order.

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 133146.jpeg   100.14K   2 downloads

 

More than likely no production LC XU1 was ever fitted with one of these close ratio OPEL gearboxes but I'll bet the HDT LC XU1's were running these gearboxes at Bathurst in 1970.

Edited by S pack, 07 April 2023 - 10:34 PM.

[yel327]

Same fiddle as the 12 bolt rear axles in HK-HG and the M21 or close ratio M21 for LJ XU1. None really ever fitted to a car and most likely the same for the M21 boxes in LJ XU1 and that closer ratio Philippines box in LC. The 12 bolts were purchased through NASCO and fitted to the car by a dealer or similar (race teams etc).

[S pack]

Same fiddle as the 12 bolt rear axles in HK-HG and the M21 or close ratio M21 for LJ XU1. None really ever fitted to a car and most likely the same for the M21 boxes in LJ XU1 and that closer ratio Philippines box in LC. The 12 bolts were purchased through NASCO and fitted to the car by a dealer or similar (race teams etc).

Absolutely.
 

[S pack]

This close ratio OPEL transmission probably wouldn't have been from the Phillipines though.

This box was an optional ratio set for the 1969 Opel GT 1900.

 OPEL GT 1900 opt ratios.JPG   97.79K   2 downloads

More than likely a quantity were imported direct from Opel in Germany and farmed out to the HDT and other top tier teams campaigning LC XU1's.

Edited by S pack, 08 April 2023 - 09:22 AM.

[yel327]

I just looked at the original homologation paperwork for the GTS327. It lists all of the axle ratios, most of which no cars were ever built in. Shows the 2.54:1 Saginaw as the only transmission but has 3.36 as the final drive, and lists as alternatives: 3.08, 3.55. 3.73, 4.10, 4.55 and 4.88. There were a significant amount of 3.08 cars built and a handful of 3.55 both of which were 10 bolts. None of the rest though which were all 12 bolt. Those rear axle ratios all appear in the parts catalogues like that LC gearbox. Interestingly they also list the same rear axle ratios in the HT homologation paperwork but also list the 3.08 12 bolt along with the 3.08 10 bolt.

[S pack]

I just looked at the original homologation paperwork for the GTS327. It lists all of the axle ratios, most of which no cars were ever built in. Shows the 2.54:1 Saginaw as the only transmission but has 3.36 as the final drive, and lists as alternatives: 3.08, 3.55. 3.73, 4.10, 4.55 and 4.88. There were a significant amount of 3.08 cars built and a handful of 3.55 both of which were 10 bolts. None of the rest though which were all 12 bolt. Those rear axle ratios all appear in the parts catalogues like that LC gearbox. Interestingly they also list the same rear axle ratios in the HT homologation paperwork but also list the 3.08 12 bolt along with the 3.08 10 bolt.

Were the 3.36 and 3.55 ratios also available in the 12 bolt?
 

[S pack]

The 2.87:1 1st gear Opel 4spd wasn't listed on the LC XU1 Recognition Docs, only the 3.428:1 1st gear Opel which is std in the 161S GTR and optional in S & SL.

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[yel327]

Were the 3.36 and 3.55 ratios also available in the 12 bolt?

There was a 3.55 but no 3.36, only 3.31.. Here the 3.55 was a 10 bolt and a production option.

[LCK186]

Hi im confused now if the close ratio gears in the opal gear box  were not homoligated, then how was it legal to be used, what do the members think

[yel327]

Same why lots of stuff not homologated was used - by putting it in the parts catalogues. Harry Firth was a master of this, one example is the Flint V8 plant 1969 Fuelie casting number 3927186. No GTS350 was ever fitted with these, but they were added to the parts catalogue as the race prepped engines supplied by GM had those heads and they were used by HDT. In this case these heads were no performance advantage over the Tonawanda 3947041 Fuelies (they were the same part number) but it was just @rse covering. There are plenty of other examples though of bits added to bulletins or parts catalogues to prove they were legitimate. Not only GMH did this, Ford did it all the time too, you just have to look at what Firth did with the GT Cortinas and even the XA-XB-XC homologation where they did @rse covering things like a "production variant" of the XA homologation during XB where "some vehicles produced with 4-bolt main blocks" and then next line "special pistons used with these blocks", and that sort of thing. They all did it.

[S pack]

Agree, there was a loop hole in the rules that allowed modifications and alternative parts to be used in competition without any vehicle build requirement placed upon the manufacturers.

This is the clause in the FIA rules.

 1970 FIA Recognition highlighted.JPG   321.5K   2 downloads

 

 

 

[LCK186]

HI it seems that they pulled a few shifties back in the 70s, seems that Ford and Chrysler also had there finger in the pie, I wonder what else they did,

[yel327]

Plenty, lots of cheating or rule bending by not just those building/homologating the cars but by individual teams. Like Bruce McPhee hollowing out his GTS327’s battery to fit a little one inside.

[Dr Terry]

It's only cheating if you get caught.

 

Dr Terry

[jd lj]

HI it seems that they pulled a few shifties back in the 70s, seems that Ford and Chrysler also had there finger in the pie, I wonder what else they did,

Offset ground cranks, the std crank became a stroker. Apparently.

[yel327]

It's only cheating if you get caught.

 

Dr Terry

 

Agree. In some cases it was more bending the rules than cheating though. I'd put Bruce McPhee's battery into that class. Harry was a master at it though.

[S pack]

Offset ground cranks, the std crank became a stroker. Apparently.

May have been more a case of racing teams ensuring their cranks were ground to make use of their maximum allowed factory stroke tolerance and choosing a matched set of conrods that are at the maximum limit of their factory length specification.

[LCK186]

Hi harry was not shifty, he was very smart in what he did, Thats why he was nick named the FOX. very slippery indeed, a credit to him.

[RallyRed]

Prob depends on which side of the fence you were on. Reckon if I was a non Dealer Team, Holden team, and he walked up at the track on Saturday morning with a box with a cam and latest gear ratios ( or whatever) and said " there you go, you now have all the latest parts, like my cars have", I'd think he was shifty (& smart).
That said, he was paid to win, and win he did.