Just to add to this great thread. I picked up a 261 a couple years back and had it machined and I assembled it to put in my 53. The engine was originally in a 1962 cab forward truck, it was delivered in the bypass mode. So the point Im trying to make is Hot Rod is right make sure you know first how it was configured, dont assume one or the other without making sure. In my case, I could of just plugged the oil ports but I decided to use a bypass filter setup, but could of easily ran it without a filter and plugged the exterior oil port with pipe plugs
and changed oil on a tighter interval.

Last edited by sstock; 08/21/2021 2:46 PM.
1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration