PART# ROCKER ARM RATIO VALVE DIAMETER PUSH ROD LENGTH (Effective)
EAN 54-55 jamb nut 1.43:1 EXHAUST all 1.51" 1954-55 3/16" radius ball 8.11"
ECG 6564 56 jamb nut 1.54:1 INTAKE 1954 1.64" 1956-59 3/16" radius ball 7.98"
ECG 6564 57 self locking 1.54:1 INTAKE 1955-56 1.78" 1960-64 3/16" radius ball 8.11"
5751066 58-64 self locking 1.43:1 INTAKE 1957-59 1.93"
INTAKE 1960-64 1.64"
as always, thanks Ted.
the above is clipped from that site, so it looks like the rocker style (with or without the self locking feature) makes the difference, weather you use the longer or shorter push rod. Assuming all the valves are the same length, as the exhaust valves are all the 1.51" and this does not recommend different push rods for intake or exhaust I guess this would be the case. So according to this, it looks like I would use the longer ones.