Of Push Rods & tappets - Drum Roll Please!

Okay, Gary...these measuements were made with a retractable tape:

Old push rod/tappet combination = 10-7/8"
New push rod/tappet combination = 10-7/8"

...so, if combination is correct, it doesn't matter which set/type you use, however:

Old push rod = 8-3/4" but with new tappet, that combination = 9"
New push rod = 10-1/2" but with old tappet, that combination = 12-1/2"

...go look at your setup to see what you have....however, now that I've measured them, I can't for the life of me fathom a shop using the wrong combination....but, if the old & new pedestals are different heights, who knows what some shop that was inexperienced with MG engines might have done....

....however, I've put old pedestals on new head, new on old heads, combined late #4 pedestal with early pedestals & never had a problem...that's what the shims are for!

Thanks Tony!! That is really what I wanted to know!! I had heard that they were the same!! Oh, I have always said that I have the bucket lifters!! They can not be mixed up!! Shims do not help, it only inhances the problem!! I think that it is possible that the valves are not seated deep enough, but how deep would that be?? Is there a spec?? Is there a height above the bottom of the head???? Thanks again!! Oh, suppliers golf tourney today!! What a fun time!! I even got a trophy!! :o)

Tony - just for grins, what are the effective lengths of a Midget pushrod/lifter combination? I think Gary may have received a mixed up parts order.
Here's why I think that. The valve adjuster's range of adjustment is only about 3/4". If his adjusters are turned in to the max and assuming that he was still able to achieve the correct valve lash, then that means that the combinations of mismatched lifter/pushrods you listed above, are out of reach for being able to achieve the correct valve lash.

Gary - here's a thought for you. Since your adjusters have run out of room, take the adjusters out of the rockers, take off the locking nut and relocate the locking nut to underneath the rocker arm. It still serves the same purpose, on top or bottom. The only problem I can think of is clearance under there during the rocking motion but that would be easy to check.

Gary - I just thought of a problem with my suggestion above. The oilway in the rocker arm that feeds the adjuster side oozes out through and by the adjuster threads. If the locking nut were on the bottom it may block this flow.

plus the other thing I don't like David, is that it throws the geometry wayyyyy out!! I think that you could possibly bend or break an adjusting screw!! I WILL get them centered!! :o) Keep thinking though!! I am still going back to Toms answer concerning a newer and an older set up with the rocker arm!! The other thing I would really like to know is how high the valve stems should be above the bottom of the head!!