Could this idea work ? Did other guys did this ? 318 infos

Yah, yah. I got that. OP mentioned keeping small ports. For a low RPM street engine, keeping port volume down keeps velocity up. You want a race car, go play on a racer forum.
I basically agreed with what you said why I gave thumbs up but Why do I need to go the racing forum ? I didn't bring velocity on super mild hop up, if the OP wants to do his mods cause of budget and whatever other reasons more power to him and be interested how it worked out. I like people doing other types of mods but if it out a fear of hurting velocity I feel he's been mislead and I'm not saying by you just in general.