Out of curiosity, I checked my 1940 manual which I would think as far as the shocks go would be close to the same. It says the shocks have to be checked and filled in the horizontal position thru the plug on top of the body which has the relief valve placed in this hole also. Says to fill to the top with GM Shock Insulating Fluid. Don't know if this stuff is available but motor cycle shops carry shock oil which might be just a 10, 22, or 32 weight hydraulic oil. Heavier the oil, the slower the rebound. Hope this helps.
Brian
