Denso Iridium spark plugs (Denso part no. IWF22)
 

I installed Denso Iridium plugs in my 68 912 (Denso part # IWF22), and actually noticed very fast start ups and probably more power (2-5 HP). While I did not dyno the car before and after installing the Denso, their web site shows HP increases for cars that have been dynoed.

(I have a big bore kit, Weber 44 IDF carbs, and an erratic 105 cam, with Sebring tuned headers, so the introduction of any HP is welcome. Use of the Denso plugs seemed to put the icing on the cake)

Overall, wanted to remark that I am now achieving very fast cold starts with 1 pump of the gas pedal prior to engaging the starter, and turnover after 1 revolution of the crank.

Has anyone else used Denso Iridium plugs?