If the times were from 1970 they were racing under 'series production' rules which means they were basically in the same condition they left the factory, with a roll cage and tyres being two of the main things allowable/changed. The only reason we had things like the ford gtho's and xu-1 torana bathurst specials (and e49 chargers) were to make the required (and I forget - it might have been 200 or 250) minimum production figures to make that model/limited edition eligible to race. Around 1973 or 74 (I honestly don't remember) they changed the rules, and got progressively more liberal, so the car had the same basic bits as the factory, but the heads could be ported, cams and exhaust were basically free, so massive changes in potential output, and less need for hi-po factory examples to ensure they were competitive.

So put in perspective, the times by the dattos in 1970 aren't actually that bad at all!