I have 1 groove intakes and 3 groove exhaust valves. Seems kind of odd. This is a mech head on my 85 na. I am having it rebuilt with all new valves. I will probable keep it and use it later on the spare real 1.6 mech TD block I have. Any issues with durability using the 1 groove vs 3 groove? Anyone else ever find a mixed bag like this?