The assembled height of the valve springs for a solid lifter 55 engine is 1.86". You can measure the distance on a new valve with the spring retainer and keepers installed from the underside of the retainer to the top of the stem, and add that to the spring height specification to get a target dimension to work with. Hydraulic lifter engines use a 1.84" spring height dimension.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!