The guy who may best answer your question did my distributor work for me. Jeff at Advanced Distributor. His site is:http://www.advanceddistributors.com/. His work on my TR6 22D distributor is here: http://www.74tr6.com/distributor.htm.
My car runs better than ever with the Pertronix and the new 69-70 Euro non emmission curve that Jeff gave me.
Good luck!
Paul
Paul Rego
www.74tr6.com