“Max effort daily driver” 318 build vs “Budget” 400 swap
Take the 400 and deck the block a .100". Buy new pushrods and ARP head bolt washers to take up the distance you milled off the block. Re-ring it and put a mild 220's duration cam in, an Edelbrock Performer intake, iron manifolds and you'll have a great running engine that will be cost effective and give you more power and torque than a small block that cost twice the money.
If you use the KISS method you'll have a lot of fun for very little money.
Tom