39 Zephyr. 3 steps backwards

[Ken/Alabama]

Got the 39 Zephyr finished and drove it for the first time to town to get front end lined up, good power and running great. About a mile before I reached the shop (5 miles total ) the engine began knocking. The oil pressure went from 50# to 30#. Coasted on into the shop and got the front end done. Drove it back home and parked it. Pulled the engine out and found all the rod and main bearings and crankshaft were shot , I'm talking bout eat up. Couldn't figuire what the hell was goin on. Nothing was blue or dis colored like it had gotten hot . All the cam bearings looked good along with the cam. After further investigation I found the two center main bearing oil holes in the block were full of dirt from what we have here in the south known as dirt daubers . Got another crank and everything is at machine shop . I've built a lot of engines but never had this happen.