Bill & Randy,

Thanks for the posts, and for the information on the S prefix.

I think that Greg Hill & Warren Foster (WD was his "handle") found a 261 block that had a lot of very odd characteristics. Warren (a GM parts professional/expert) mentioned something about it being a later replacement block.

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.