i just got done building a 350 for my car and didnt want to dump much more money into it but i found a good deal on a 400 block so if it ever stops raining ill pick it up. its basicly the hole motor but its in pieces. im getting it from a kid at work and the guy he got it from said it ran but smoked and needed rings. im getting it all for $100. i thought about selling the 350 but theirs no way in hell i'll get any where near what i put in it so i'll either find something else to put it in or keep the 400 for when ever i need it.

Why not drop in the 350 while you build up the 400?

Speaking of which- get it thoroughly checked for cracks before you put ANY money into it. 400s have problems with cracks down on the main webs and up on the deck surface around the head bolts, steam holes and between the bores (my opinion- there's just too damned many holes too close to eachother in the deck surface of a 400!)