I've seen the Fordstrokers kits. They look really nice, but $2k for just a block and internals is a bit spendy IMO. I'd be more tempted to buy elerm1's 302, then take a trip to the machine shop and maybe buy a new crank and higher compression pistons. Then I'd have more left over for a TFS or whatever. The 306 crate is pretty tempting though, even though 340 hp is getting a bit on the low side for a modded 'Stang. IMO anyway.
I dunno about the crate route. Part of me wants to do the entire build myself, but another part of me is afraid of screwing it up.