Be a shame to lose the original engine - and I assume also the five speed box (says the two faced he who is fitting an Aprilia engine into an Augusta) - BUT how about an AMR300 blower? They're tiny. Link below.
The other random thought - with the van's gearing would it make a classic (MCC) trials car? It must be pretty capable given the hills in Italy and the state of their roads post war. I bet its a proper little mountain goat. No trouble with getting ballast over the rear wheels either!! I'm not 100pct sure of the regs, but I think that keeping standard gives you the easier routes and less severe stop-starts etc.
Then again - if the motivation is something for the business - I can see that being able to get somewhere and back, in short order, outside of a major city, with a reasonable load, you'd want a bit more straightforward reliable power as an Aprilia would give you...or is it Appia power you have earmarked??
David
http://www.autospeed.com/A_110294/cms/article.htmlhttp://www.adelaidejap.com.au/Turbos%20&%20SChargers.htmI think this guy has one - it was on his stall at Prescot and very tempting for an Austin 7.
http://www.7ca.co.uk/index.htmTo quote from the autospeed link: "Fitted to upmarket versions of the Japanese-market Subaru Vivio/Pleo, this blower is lightweight and can be squeezed in very tight engine bays. It measures approximately 18.5cm in length (including the pulley) and the main body is around 15cm wide and 10.5cm tall. Although fitted by Subaru, the blower is manufactured by Aisin and is coded AMR300. This code suggests it displaces 300cc of induction air per revolution.
The 660cc supercharged Vivio engine is rated at the class regulation 47kW and has 84Nm of torque, so the AMR300 blower is suitable for only low power applications. This makes sense when you look at the small 45mm OD blower outlet pipe.
We’d be reluctant to push the AMR300 supercharger past 70kW - which means it’s good for only sub 1.0-litre engines."