Posible swap for my 273 Barracuda 1966

Now I have it with Crane Cam, Holley carb (650?), Edelbrock admision, free exhausts... but I want more power. I think in a engine swap... but I don't know if is better small or big block because of the ensamble difficulty. Here are 318, some 340/360 and a 440 stroked 😍.

What I need? I have no idea about engine mounts, cables or anything else neccesary for this... I need a idiot guide haha. Or if is a good idea conserve 273 block and do something with it. Here blowers are no legal. Thanks. Web I can I Will post so me photos.