I've almost finished machining the support bars for the rocker arm studs I'm planning on using to position a set of big block Chevy V8 roller rockers on a stovebolt six cylinder head. The next step will be installing the rocker support studs in the right position so the roller tip on the rocker arm will be positioned correctly over the valve stem tip. I've made a fixture that plugs into the valve guide and has a hole for a transfer punch to mark the support bars the correct distance from the guide centerline. That will assure that the geometry on all the rocker arms will be the same. Then the height of the rocker assembly will be set by using an adjustable length pushrod so the rocker tip will be at a 90 degree angle to the valve stem with the valve halfway open. Once the pushrod length is determined, I'll order custom length pushrods with the right tips on both ends. At least one engine that's under construction now is also going to have roller valve lifters from a MOPAR 440.

This type of geometry exercise is done on racing engines all the time. Once I have a running prototype engine and some dyno figures, I'm going to approach a CNC machinist friend about making a small run of the support bars. Assuming the dyno tests are successful, running stud-mounted roller rockers might just solve the problem with the short supply of good condition used rocker arms and shafts for 216 through 261 stovebolt engines, and maybe decrease the running friction of the shaft-mounted rockers as well.
Jerry

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