Hi Julian,
Welcome to cc.come. As you've already found out this is an AWESOME site!! So keep us posted on the project!! It looks nice. You can get a lot of performance from a 318 if you decide to stick with that. I had a 73 Barracuda with a 318 that I managed to get to run in the 13's with a 318, stock lower end, converted to a torqueflite 727, stock rear end, hedders, some head work and a decent 4 bbl!!
Matt B.