A lot of books written here. Here is my finding. I had a low mileage 1973 318 auto out of a Charger.
I pulled the 408 out of this Duster and needed a motor and trans to stuff in the car for resale. So I used the 318. I didn't want a 2 bbl because I wanted to use all the 340 parts on the motor such as valve covers. and air cleaner and throttle pressure.
I installed a Weiand intake and a 750 comp series carb. 273 single point distributor. After the front end alignment I had a buyer for the car. Took him for a ride and I could not believe the way the car performed neither could he. Rolling along with the factory 904 high stall used from 71-73. 323 suregrip. and 275 15 goodyear eagles. It turned the tires from a 5 mile an hour kick through low and about 5 foot in second. The motor never fell of in RPM's.
So you can write three books. It never equates to the real world. What I can tell you is some motors just work and some with the same modifications don't work at all.
The most important part of building a motor is Balance. Pressure balance and weight balance. Several grams out can't be felt in the car in vibration. But very noticable in performance. That is why some run and some don't. We just got a BB Pro balanced stroker crank from Scat it was 18 grams out. We had some here that were out even more from race motors that were here for refresh . They were run with cranks out of the box. Very Very big difference after balanced.
Some 318 motors make power. Cut reciprocating weight everywhere you can. Pencils and papers can only suggest opinions...
