Plug wires-I’ve has MSD, Ultra40’s and Firecore over the years. Each supposedly better than the last and never have I seen one bit of difference. I’ve always disliked the MSD’s and how they don’t “click” on as good. But never changed any et.

Good clutch-screw the torque converter.

10deg locks vs 7deg locks. Last time I had the heads freshened he was all about I think going from 10 to 7. Spent a bunch on ti retainers and locks. The time before that I could have swore he wanted it the other way. I don’t remember. But I have never seen a change in lash, et or anything else from one to the other. Heck if I know.

My M/T 3074s were worth .03 in 60’ over Phoenix. A little lighter and seem to last a little better.

I bought a used 1250 Doninator years ago from a local guy. Threw a kit in it and away I went. Sent it to Pro-Systems couple years later. $600 bucks or whatever it was. No difference. Maybe idled a little cleaner. I still wonder how much it all matters in a stick car that’s never below 5k but I’m not smart either.