Ron
Hi Aussie 4 speed has the same external dimensions as 3 speed all synchro and trimatic it is the gearshifter that is the problem as the strengthening crossmember in the floor is in that very location.
We all have owned or seen cars with this cut out but legally it’s frowned upon.
A possible alternative would be to set your floor shifter up in the Saginaw location bolted to the floor like as in an early Opel 1900 Torana 4 , though from memory the action is clunky .

An aussie 4 speed can be fitted to a ht/g if desired. But as said the shifter doesn't fit, clashes with the under floor cross support. Don't butcher that as other people did in the day.

The trick is to make the shifter hole in the original position of a ht/g saginaw or opel shift and mount the Aussie shifter on top of the floor (might have to custom make a flat piece of metal to suit the hole) . Then it's just a case of lengthing the 3 rods by about 4 inches at the same time making sure they are the right shape to fit around the cross bracing.

I then cut a section out of the shifter so that it is probably half the length of a typical hq/j one and it falls beautifully yo hand and shifts are nice

Edited by user Wednesday, 27 October 2021 8:17:22 PM(UTC)  | Reason: Not specified

Ron
If the 253 traumatic combo has a gear selector on the right side eg was column shift. That’s a good option as you will only need to change the sump and pickup and you would have a column shift paddock runner.
The tail shaft and diff / yoke would need upsizing for rego.
You have Toowoomba swap in a couple of months.
I saw a v8 flanged 2.78 at rocky swap for 80 bucks but it was drum to drum and we were in our polo. Would have been value as it was a long bolt centre.

All 2.78 and 3.08 are the long bolt housing. There were no 3.36, 3.55 or 3.9 V8 banjo centres, only 2.78 or 3.08. $80 is cheap today though for a HK-HG 2.78 banjo, possibly LSD as well as most HK were

Edited by user Thursday, 28 October 2021 9:20:31 AM(UTC)  | Reason: Not specified

GMH only ever fitted 2.78 or 3.08 banjo to V8 cars, be it HK-HG or LH-LX. 2.78 was built for HK 5L and 3.08 for HK 253. They were initially nodular carriers when built by Borg Warner whereas the other 6cyl ratios (3.36, 3.55 and 3.9) were GMH grey iron. GMH later used 2.78 and 3.08 in some 6cyl applications like LC and later LH Torana but never used 3.36-3.9 behind V8. They did offer a 3.08 in HK GTS to go behind 186S and M21 Saginaw but it was a V8 diff with a unique tailshaft to suit.
If an LH SLR5000 had a fine spline banjo in it, it at least would have been made using a HZ or possibly an LX centre with a V8 yoke added. All 5.0L LH-LX will be 2.78 LSD banjo with some exceptions like L34 with close ratio M21 or the rare retail order car with a 3.08. Just about all 4.2L LH-LX manual will be 3.08 banjo, from memory auto got 2.78.

Wasn't the 3.36 rear axle an homologated option for an L34 ?

Dr Terry

It may have been a homologated option as a sneaky way to allow LH to race with an alternative rear axle ratio but GMH would never have built one. Just like 3.9, 3.36 and 3.55 A9X rear axles. Or M21 or close ratio M21 on XU1.

Plus the homologation is not for L34 anyway. You’ll notice they added 3.36 as an optional rear axle twice in 2/2V on 15/5/74 and 12/4V on 1/10/74. Why? Who knows? The homologation is for LH SL/R though not L34 and yes the 3.36 rear axle was optional on LH SL/R as the performance rear axle ratio behind the standard 3300 whether M20 or M40. The whole LH homologation is for LH SL/R and later into LX SL/R with SLR5000 and L34 both treated as variants. The LX is an evolution of type on the LH.

I just had a look at the LH features manual and there are no optional rear axle ratios for any V8:

L31 M21 or M40 - 2.78 LSD
L32 M20 - 3.08
L32 M40 - 2.78
L34 M21 - 2.78. There was a close ratio L34 M21 and it came with a 3.08.

LX is the same, except A9X had the "optional" MC7 but either it or the standard M21 had 2.60:1 standard with no options. Sometime during scheduling the A9X specification changed from G70 to GU4 rear axle and that is why some A9X are 2.6 and some are 3.08, but there was no optional rear axle.

Edited by user Friday, 29 October 2021 3:15:36 PM(UTC)  | Reason: Not specified

I have never seen an LH SL/R manual with a GV4 rear axle, although auto versions maybe I’ve seen one? Can’t remember. All Gpack were 3.36 though.

Pine Rivers had their annual show postponed because of Covid lockdown. Their show day public holiday was also on the 29th October to coincide with their 3 day show rescheduled to the 29th - 31st October.

You have to change the sump, pickup and dipstick anyway to fit a 253 into a HG, it doesn't really matter if its from a Commodore which VR prefix is. If it has a 4BBL intake and Quadrajet it may be a blue 4.2 which is all good, just have to watch that to the letter of the law in most States you need all pollution gear but normally wouldn't be applied today. They way to tell if its a blue or red engine is by the intake - if it has a single bolt in the middle on both sides it has red heads. If it has two on both sides it has blue heads. I could also tell you by the digits on the engine number.

If you did get it you'd also need a pair of HQ-WB 253/308 engine mount adapters and exhaust manifolds. Hopefully if it has a Quadrajet it comes with a factory 4BBL air cleaner as these are worth big $ to buy now. Also hopefully it has the HEI dizzy on it still. If you do get it factor in $350 for a Quadrajet rebuild, worth every cent.

I don't have FD as a valid Trimatic code but it may be an obscure one. Most seem to be FR for left shift Commodore 4.2. I any case they can be swapped over but you'd have to get it done properly by a Transmission shop, and you'd have to find an old HQ-WB or LH-LX or similar RH shift 6cyl box to get the internal shift mech as these boxes are natively left side shift and have an internal crossover mech to convert them to RH side shift. In the end it may be cheaper to get teh transmission shop to swap all the good V8 bits over to a 6cyl case. Talk to them first before committing.