Thanks for the replies! Duane and Jamo - interesting timing as I'd (unsuccessfully) tried to find more information to verify that the car's actual age, and I received an email from John @ Kassabian asking how my enquiries were going. Without making original documentation appear from thin air, I can't import the car. Forging registration documents will land me in prison or with a HEFTY fine over here, so that's not even a consideration.
Duane - you said
"a nice solid (STOUT) chassis, legroom, and some other interesting challenges to work around".
Just to make sure, do you mean
It's a solid chassis with good legroom, but other interesting challenges... or
It's a solid chassis, but there are legroom (and other interesting) challenges...?
Sorry - I just want to make sure about the legroom, as a 6' and a 6'4" 240lb driver will be the two main people driving the car. I don't mind modifying pedals/seat/dash to make it more comfortable, but if it's really bad to start with I might be in a lot of trouble.
I'd be very interested in your thoughts about challenges (if other than your interesting point about the rollbar) if you have the time
Some excellent other general comments about Arntz/Butlers - thanks!
Jamo, I recall how well old #5 went in SCCA events, and how you regularly made much more expensive cars look a bit superfluous.
I've come to an agreement with the seller of another big block Arntz (with some more documentation) that if I gain Australian customs import approval for the car, it's a done deal. He's been good enough to hold it for the week or two until I have the approval. It has a Fuel Safe sticker on the cell, but I'll definitely verify the age of any bladder or foam as a first precaution.
Thanks again!