I'm building a 461 stroker with Speedmaster heads and I need to order pushrods.
I initially used the method where you put a dry erase marker on the end of the valve
(thanks Fast Monty's Garage!) and the rocker arm wears the ink off-- I got 9.135" on all valves.
Before ordering, I asked Butler to help me make sure I was doing it properly since they're hydraulic roller lifters and there are a lot of opintions out there. The Butler tech said he was certain I would wind up needing 8.800" pushrods and I must have done something wrong. I decided to keep learning and measuring until I got closer to that "known-correct" goal.
I thought that maybe the lifters were collapsing? I swapped to the checking springs and did it again. Got the same result.
More research, I found
this video from Straub that explains the whole goal is to have the rocker arm be square to the valve at 1/2 lift. That makes a ton of sense.
I reset everything, drew a line on a rocker, have my checking springs, got it as square as I could by eye, and the pushrod came out to (drumroll please)... 9.135"! Literally the exact same as Monty's video.
The Johnson lifters want .035" +/- .010" of preload, so I think I need 9.170". They come in .050" increments so call it 9.150" pushrods.
Am I doing something wrong or is the Butler guy just remembering measurements from different lifters/rockers/heads?
461 with 10.230" deck height.
Speedmaster 72cc heads, round port.
.027" head gaskets
Johnson lifters 2112OPR
CompCams 1.5 ratio roller rockers CCA-19060
Thanks!