Last step today was to verify pushrod lengths using the Morel lifters when rotating the engine. I kept in mind that the lifters will compress slightly so this was to look at start point and general range of motion at the valve stem. General descriptions are in the pics, which are readable but not as sharp as I'd like. I think I had some oil or something on the phone lens.
Pushrod length 7.44" with Morel, no slack in pushrod, no preload added to lifter. This is just looking at the base lobe witness mark.
Witness mark is generally centered, 1 turn (.050") lifter preload added, with consideration that the lifter had probably slightly compressed during the rotation.
Pushrod length 8.50" with Morel, no slack in pushrod, no preload added to lifter
Witness mark generally centered, very slight offset to outside,1 turn (.050") lifter preload added, with consideration of probable lifter slight compression. Still looks acceptable.
Previous check with modified (solid) Melling lifter was:
Intake - 7.518"
Exhaust - 8.58"
Today's check with Morel hydraulic lifter was:
Intake - 7.45"
Exhaust - 8.50"
Looking at the witness marks and taking into account an adjustment window of .050", it seems that workable lengths would be:
Intake - 7.5"
Exhaust - 8.5"
But again, this is not using the lobe mid-rise position of rocker arm to valve stem as that is not perpendicular. If I make it perpendicular as a criteria, then the witness marks move too far outboard (almost to edge of valve stem) because that necessitates longer pushrods.
As a sort of quick check I looked at the difference in stock pushrod lengths vs what I came up with. Stock intake pushrod length = 8.28", exhaust pushrod = 9.25.
If I compare my numbers, there is a .78 difference in intake pushrod length and .75 difference in exhaust pushrod length, virtually the same difference for both when you take into account my measurements may not be exact to the thousandth. So this tells me that using the taller Morel lifters yield about the same result in pushrod length reduction which makes sense to me. If there was a greater difference in the numbers then I would look at what I measured wrong. So I believe that the lengths I came up with are valid.
What I can do now is use the Melling solid roller with the same pushrods and rotate the engine to check piston to valve clearances. If clearances are ok with the Melling setup then they will be ok with the very slightly shorter final Morel setup. Hope that makes sense.
I also found that the new Comp Cams guides were shaped slightly too high at the pushrod ends and slightly rubbed on the rocker trunion. I'm returning them and re-using the Manley guides, which are shaped with a bit less rise and fit fine.