why don't the wishbones out of the book fit sierra hubs. i wiil be very happy if some one could tell me y and how to make them fit

The book plans are all around escort bits and bobs - hence it don't fit a sierra upright. There is a mushroom insert MK make that fits into the top of the Sierra upright and allows adjustment of the castor of the wheel.
I *think* this allows the standard wishbones to be used with a Sierra upright.
I think Jay had seen a pair of these inserts advertised on ebay recently.

cheers, thanks for the track day thing

read this thread as well. There needs to be a modification to the upright as well.

http://www.locostbuilders.co.uk/viewthread.php?tid=7636