Low Budget 300rwhp engine. Please Help!

[mattr762]

As some of you know I'll be getting a Cobra soon. Here are some of the engines I'm considering based on my wants and needs:
- 4.6L modular SOHC (used for $2000) 230rwhp stock/270rwhp with simple mods
- 4.6L modular DOHC (used for $4500) 270rwhp stock/300rwhp with simple mods
- 302 Price ??? anywhere from $1500 to $6000??? HP wide range
- 351 Price ??? anywhere form $1500 to $8000??? HP wide range

Needs:
- Costs $2000
- Cobra as a daily driver (weather permitting) 40 mile commute
- 20mpg +
- Easy, reliable starting (even for the wife) including cold starts
- Easy, smooth driving (wife's gotta be able to handle it)
- About 300rwhp
- Occasional racing
- 12-12.5 1/4 mile
- Light for auto cross/track

Here is the main question:
Can I build a 351w that fits my needs?
Do I have to go to the salvage yard and find one for $500 and rebuild it myself? Do I really need forged crap and blue printing? That seems to add a ton of dough.

Please give me ideas.

Thanks,
Matt