I had to go back through your old posts to confirm what engine you have before offering info. It's been established that your block is a
'54 235 Truck and the head was an earlier '53 casting, but still suitable for your block.
You can find the full '54 truck engine oil system description on these two pages
Page 6-5 and
Page 6-6 of the '54 Chevy Truck Shop Manual.
Nothing in there indicates there is a "restrictor" of any kind in the small oil line under the side cover.
Curious to know why you asked?
