70 dart 318/904/7.25

Then don't let a couple of weeks stop you from getting what you want. Really, what is the real difference if it's done in 3 weeks vs. 5? It's going to cost you at least 500 bucks to do a low cost build as I did. And time.
As mentioned above, if you use the 318, it's going to appreciate a decent torque converter, especially with your gears.
If you want a quick run down of a parts list for your 318, then here it is:
4bbl (125.00 - 225.00 2nd hand bolt and go)
4bbl intake (dual plane 2nd hand 125.00)
around a factory 340 size cam/lifter kit (new 110.00 cheapy from summit)
headers. (135.00 cheapies from summit)
gaskets - (50.00 bucks)
Timing chain - (35.00 summit double roller)
Heads - minimum a valve job. Could always home port. $$$$ unknown......