what engines going in it then?
could you use Scaffold pole? may be easier to get hold of. just a thought.
google search "BEJ Engineering" they have 42.4mm in their ebay shop
postage seems reasonable enough too.
good luck.
looks good, one project i've seen was a mid mounted 4.2 v8 audi engine in a mini, it was a pretty tight fit but never the less it was a beautiful job.....
l am going to have the doors opening and a chopped down front screen rather than aero screens.