[Jac Mac]

No there is not a lot of info about, I had a look for an article when it first appeared in some old mags last night ( problem with that is you tend to get sidetracked on other interesting stuff as well ) still have not found it!
Yes you are looking at huge torque figures. The chain was in that extension housing / back hat of the rear axle- you can also make out the top/bottom rod ends of the large trailing arm that located the axle. I would hope it had a locked diff, the difference in axle lengths would add a 'new' dimension to the handling under acceleration/deceleration for the driver to cope with if a differential was fitted.
Dont believe any serious attempt was made to increase power by internal mods, the car was built over a relatively short period of time like most racecars of that era, Its only the restorers who take decades to rebuild them ( usually complete with all the original flaw's ).
Cars like this result from an idea over a couple of beers on a friday evening and are built during an off season with the dream of blowing last years champ off his perch-a really good season resulted if several groups have the same idea! This one stuck out because of its raw simplicity, its one of those cars you walk away from thinking " that wont work & about 10 seconds later- yes it bloody well will !"

Jac Mac