Yes your engine is full flow capable, however as you said it is in the bypass mode. I left mine in the bypass mode because I was unsure of the ramifications of pushing the pin in. Once it is in there is no going back. How far does it go in to get into the full flow mode, I have heard about 1/2" but cant say for sure. Thinking you could use a suitable 40oz hammer and correct size punch.
Interesting to know my 62 year 261 was delivered in a cab front truck and delivered in the bypass mode from the factory.

Last edited by sstock; 03/07/2021 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