Somethings radically wrong here there is no big block chevrolet I am aware of that has an installed spring height under 1.88". So somethings definitly wrong here, even stock valves in these heads should measure about 1.900 to 2.10" from the valve retainer bottom to the bottom of the spring pocket. Have them try a set of +.050" locks or a different retainer lock combo, maybe they can get to the 1.88 to 1.920" installed height you need. Possible, vlave stems short, someone has the valve seats in too high or the valve job is high. Not sure, but somethings not right here!

Ray @ Raylar

Yea, Im running stock length springs in my 781's with 1.9 length. We did have to cut the spring pockets, a lot in one head. (intakes only, the exhausts are deep due to the rotators and will need cups). There are castings that ran short springs. These guys should know this, 781's are common performance heads. Run

Quick,
Did your machine shop install new valve seats ? If so, maybe they did not machine them deep enough. If I remember correctly, the valve stem height should be about 2.100" That is the dimension from the spring seat to the tip of the valve. I agree with the others, almost every Rat head I have done easily has 1.850 -1.900 installed hgt with Comp retainers. I wonder if they are using the wrong locks for those retainers ? I think I would pick up one of the heads and check them myself.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Thank you all for your responses. It is only the intake side that will require a valve change at this point. The exhaust has the room due to the rotators. I will be checking into this further.. I may have one of those... short spring heads..