This post is inspired by the request from wb56 for a 24810-52 upper crankcase stud. Looking through some drawers I came across four crankcase studs. One shorter and three longer studs. The parts book calls out a 4-5/16" length for all K models. The bottom one in the picture had acorn nuts on each end and a 1/32" copper washer for both sides. This one measures exactly 4-5/16". I am assuming this is an original K Model stud. The other three are the same diameter but are 4-9/16" long with a short machined area on one end. They are both 0.278" in diameter. I have a bare set of early K Model cases. Across the cases where the stud goes measures 3-7/8". When I put the 4-5/16" stud through there with 1/32" washers on both ends you only have 3/16" of usable thread sticking out of each end. That's not very much. With the longer studs if you bottom out the acorn nut on the machined end and stick it through the cases with washers you get 9/32" of usable thread sticking out. That seems more acceptable then the 3/16" with the shorter stud. I believe these longer studs would work fine for a K Model application.
A major question I have is, has anybody else seen this type of stud? Was this a revised part without a part number change? Could they have changed when in 1956 they added the 27434-56 carb. support nut?
If anyone has any insight or comments on the subject would love to hear them.
Stan