Oil dipstick port problem

[thedudeabides86]

I have a silly problem. I had a poopy 305 in my '72 Chevy 3/4 ton and pulled it for a used, strong 350. The 305 had no recessed shoulder in the dipstick port and the 350 does. This shoulder that is recessed blocks me from getting the dipstick properly inserted into the block. I'm trying to get this truck running before the Gearhead Get Together in Maple Lake, MN on Saturday. www.gear-headgettogether.com

Anywho, I'd really rather not have a mundane issue like this slow me down. I really need help in figuring out what I need to do to remedy the situation. Thanks in advance! See picture below of said recessed shoulder.