I'm no expert on roller rockers, and luckily the two engines I have that have them were done when I got them, but I do know that when you install the guideplates they are secured by screw in studs, and that the heads need machined to accept these. I also remember that it is more than just tapping threads in most cases, you have to have some of the boss machined down to lower it a little. I think the guide plate kit will probably include directions??

As for different length pushrods, I didn't know these existed until I took my newly running 302 in my '27 in to have the exhaust system done. When it was all capped up and quiet, the guys at that shop (who build race engines) said it was not running right. Sounded ok to me, but they really know their stuff. I told them to fix it, so they installed shorter pushrods to correct the geometry and when I picked it up the car did sound much crisper and ran better. Maybe the head surfacing took off material that changed the length needed?

All this finite stuff is way beyond my pay grade, so I leave it to experts, like some of the guys we have on here.

Don