The Ford Barn - View Single Post

Daves55Sedan · 11-01-2023, 06:51 PM

Fomoco made rocker adjusting studs with locknuts for the '54 thru '56 model years. In '57, they went to a combo resistance fit stud with integral bolt head. Obviously, the '57 and later are easier to adjust on a running engine, but there is a catch.
The '57 and later adjuster stud threads wear down after a while, so they can begin backing themselves out of the rocker arm. Not good.
.015 final hot adjustment is fairly tight and may permit a small amount of compression to escape before it should on the upstroke. I would be more in favor of a looser than .019 adjustment, whereby, the valves are both closed for a longer period of time and allowing compression to build up.
I can recall many folks in the old days having them all adjusted fairly loosely like this on purpose, but they had to get used to listening to the engine "chattering" louder. OTOH, you can't make them so loose that you won't get enough intake AND possibly bend a pushrod or two either.
The factory seems to have settled on the happy medium of .019 for best performance.
As far as to which type rocker studs are better? I like the older '54 - '56 studs with locknuts, but I'm more about longevity with my repairs.

11-01-2023, 06:51 PM	#9
Daves55Sedan Senior Member Join Date: May 2010 Location: Granite City, Illinois Posts: 3,008	Re: Rocker Arm Shafts Fomoco made rocker adjusting studs with locknuts for the '54 thru '56 model years. In '57, they went to a combo resistance fit stud with integral bolt head. Obviously, the '57 and later are easier to adjust on a running engine, but there is a catch. The '57 and later adjuster stud threads wear down after a while, so they can begin backing themselves out of the rocker arm. Not good. .015 final hot adjustment is fairly tight and may permit a small amount of compression to escape before it should on the upstroke. I would be more in favor of a looser than .019 adjustment, whereby, the valves are both closed for a longer period of time and allowing compression to build up. I can recall many folks in the old days having them all adjusted fairly loosely like this on purpose, but they had to get used to listening to the engine "chattering" louder. OTOH, you can't make them so loose that you won't get enough intake AND possibly bend a pushrod or two either. The factory seems to have settled on the happy medium of .019 for best performance. As far as to which type rocker studs are better? I like the older '54 - '56 studs with locknuts, but I'm more about longevity with my repairs.