What tool to use when installing keepers?

[lukenag]

I know that, but i have gotten two different valve spring compressors, one wouldn't work because the head walls are to close the the valve spring to grab and compress it, the other reached around the entire head with one part resting on the bottom of the valve and the other side was ment to rest on the top of the spring and compress it, but the spring was to deep in the head for it to make contact with it and compress. Just trying to see if anyone has done keepers on the 420a head and know what compressor or what tool works best for the procedure.