Started this to get away from Chriso-k's thread about his turret replacement, plus in discussing/arguing with Aaron about the G-pak's importance or lack of it some interesting stuff has come to light which raises more questions than it answers. Please feel free to add anything.
Firstly, why did GMH make the thing in the first place? They already had the SL/R, and all the Gpak was going to do was poach sales from the SL/R. Perhaps the answer lies in Norm's book where he says that sales were sluggish of it and many had to be sent to NZ to get rid of them, or words to that effect. Maybe it was an orphan before it was released and its release was a mistake? The SVP code for the car is XV1, and given the HQ SS is XV2 tells us the actual timing of the application of the codes is around the same time (note that codes were allocated in order, so XU8 was followed by XU9 then XV1. The V8 XU1 was XW7, so you can see XV1 and XV2 were allocated before the V8 XU1 was given a code). Off track for a second, given it was a late decision by GMH to cancel the HQ GTS coupe meaning HQ only had a V8 GTS coupe perhaps means that the SL/R was at some stage also going to be V8 only? Which would explain the need for a "sports" version of the LH 6cyl which the Gpak was. Looking at the timing of XV1 and XV2 together the Gpak and the HQ SS and their package similarities starts to make sense in that regard. However the HQ SS was released into the HQ model mix (albeit replaced soon after by the XV4 GTS sedan) as a stand-alone vehicle that was never gong to impact any sales other than those of Ford's GS/GT sedans or Chrysler's Pacer, whereas the Gpak was released in direct completion with the SL/R. Think about it today, if you could buy a 6cyl manual VF base spec Commodore with a lower ratio rear axle and a few sports options that screamed its head off at highway speeds for say $35,000 or for a few thousand more you could have an SV6 what would you choose?
What the SS and Gpak do share though is they are both performance wise superior to their similar vehicle in the same series (or they vehicle that replaced it in the case of the SS). The Gpack with its 3.36 rear axle and lower weight would have felt much faster than the SL/R with its 3.08 rear axle (anyone who has road test 0-100 and 1/4 mile times and trap speeds for the Gpak and LH SL/R please add). The HQ SS was lighter that the GTS sedan that replaced it and with the extra power of the SS courtesy of its dual exhaust system and lower gearing with its 3.36 rear axle saw road testers manage to pull a 16.9s quarter mile time out of the car - the stock GTS with its single exhaust and 3.08 rear axle was a slug in comparison (road test times to come). In fact one magazine found a 253 3spd Kingswood sedan to be faster as the M20 and 3.08 combination with 14" tyres was not a good combination for quick acceleration. Road testers of the new 308 manual GTS sedan (with single exhaust and 3.36 rear axle) made comparisons to the SS, tests for the 308 manual GTS sedan returned 16.5s quarters (will add more data as I find it). Note that until this time all 253 and 308 GTS's came standard with single exhaust. The HQ SS was the first of its kind, it was standard with dual exhaust, only the GTS327/350 before it had N10 as standard. Hence the surprise of the magazine testers of the day - they'd been used to standard V8 GTS coupes with their 3.08 rear axles until they tested the SS.
Co-incidence or not - the LX SS Torana all had dual exhaust outlets just like the HQ SS? Did the VH SS Group1-3 standard vehicle (as in the 4.2L car) have a dual outlet exhaust as standard?
