Can you swap set screw/ lock nut adjusters with the interference fit adjusters on the rocker arms

Gary Ryan San Antonio.TX.

Yes you can - I had to do it  for one valve.  However, depending on the push rod, it may be tight to get the .019 gap.  When I did it, it was close, but worked. The interference thread  is in the adjuster, not the rocker arm.

The adjuster and the lock nut are available - Mummert has them, just saw his video


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

thanks for the info.

Gary Ryan San Antonio.TX.

I only use the adjustable lock nut style on all my engines. Just remember when you have what you thing is perfect after you tighten the lock nut it will be loose about .001”.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I have interference AND locknuts (belt & suspenders). The added valve gear weight is likely a viable trade-off for maintaining an accurate gap for longer (?). I also think a long hex wrench is easier to use than a screwdriver if you want a precise adjustment.

6 VOLTS/POS. GRD. NW INDIANA

Can anyone let me know of a source for the interference type of adjusters?

While I do not have a source for new interference fit rocker arm adjusters, Smith Brothers Pushrods does offer a set of jam nut adjusters for $108.  If it helps, the Y adjuster is the same size as the adjustable rocker arm adjuster for the Ford FE (352/290/406/427) which may help to broaden your search parameters.

Lorena, Texas (South of Waco)

For those using both or just wanting to lighten up rockers; you can use “pal” nuts which are less than 1/2 the thickness of a regular nut or make them from aluminum. I made the ones for my GMC 6 race engine. Bought hex stock, drilled and taped for the adjuster, and cut them on a lathe. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.