I did a 400 HO and a 389 a couple of years ago. Have a look at my videos. I built a engine test cart.
I don't believe you will feel much resistance by turn by hand unless you have a lot of mech adv with your tool. Just put the tool in and run her with the drill. See if you can feel the torque and the oil flow. Also, do you experience rebuilding this engines? I'm assume you know how to break them in.
See what reading you have on your oil pressure gauge (oil in a tube type of gauge)..
I'm a little concerned about the grinding off the barb on the oil pump rod. We made the same mistake but fixed early on. When you use a test stand it makes life worth living !! lol It's so sweet when you can do a job, just yourself and no climbing under the car, everything is just right there front of you.
Engine Test Stand Playlist: https://www.youtube.com/playlist?list=PLwoxyUwptUcdqEb-o2ArqyiUaHW0G_C88 restoring my 1968 Firebird 400 HO convertible (Firedawg) 1965 Pontiac Catalina Safari Wagon 389 TriPower (Catwagon) 1999 JD AWS LX Lawn tractor 17hp (my daily driver) 2006 Sequoia 2017 Murano (wife's car) 202? Electric car 203? 68 Firebird /w electric engine 2007 Bayliner 175 runabout /w 3.0L Mercuiser__________________________________________________________