The fronts are fine, but the backs aren't. You need more offset than a B4 wheel offers, and unless yours has been changed you'll find it has a larger diameter axle than the B4 uses.
Its
JC racing not J Concepts - They don't currently have RC10 ones on ebay but email and ask.
I remember Keith and Kristian, don't remember Graham. I'm Simon Davanzo, raced there in the early 90's till I went to Uni - my brother Andrew raced there a while longer.
Love the Radioactive sticker on the shell - that takes me back!