273 rockers

To change the factory style 273 rocker arms to a adjusting screw and lock nut, what if anything needs to be done to the rocker arm?

Just spot face the area where the nut will rest.

I'm assuming the spot face is to help the nut sit flush? Does it have to be done on a lathe or could a sanding belt be good enough?

I did mine on a mill. I suppose you could do it on a drill press with a center cutting end mill. And yes, it's to give the nut a flat to tighten against.

Where do you buy the replacement adjusters? I got a set of those rockers in my junk.

Isky sells them, among others.

https://www.pushrods.net

The factory adjusters are a tapered thread. All you have to do is chase them with a good 5/16-18 or 3/8-24 tap (can't remember which) to finish them out.

I've done 1 set already, but haven't spot faced them yet.

My old Sig Ersons were interference fit.They finally started backing off after 30 plus years.Bought MP adjusters and they fit perfect.Still running them and adjust maybe once every 2 years.Rocky