They are either mis-labeled or they are the wrong seal altogether. Umbrella seals fit fairly loosely over the valve guide and seat on top of it as I and Randal have already mentioned. Your seal is getting smashed between the top of the guide and the bottom of the retainer because is has an interference fit on the guide itself and isn't seating fully on top of it. The seal should also fit inside of the valve spring with plenty of room to spare and not rub it. If it does, then either the springs are requiring the use of a smaller diameter seal such as a teflon style that requires the guide to be machined to install them(assuming the umbrella seal is the correct one and not mis-labeled), or there could have been a better choice of springs that allows the use of the stock umbrella seal to begin with.
Looking back over this thread, you said you were thinking about using a particular Howard's valve spring, but you never said if you actually selected those or something else. What part # valve springs does your cam card say to use?
