Hi
Firstly, a very warm welcome to the forum
If memory serves me right, Chris Gibbs & his brother built a Roadster that used BMW donor parts.
He posted an example of what needed to be done to the BMW front uprights, it's the second post in this thread.
http://www.haynes.co.uk/forums/showt...t=bmw+uprights
Sorry there are no dimensions there but should give you the general idea
