My combo- 400+ n/a hp ?

[420nitro]

I'd say with a 306, it would take something like:
a set of Afr 185 heads
10 to 1 compression (min)
Your intake (air gap) or victor jr.
650 speed demon carb. (no bigger)
1 3/4 long tubes with a 3 inch exhust
comp cam extreme 274 hr cam

If you were to stroke the engine it would only only make it easier to make the power goal you have. Now don't forget that tuning is worth more then anything! If your tune is off you aint going to make shyte.
So a good ignition and dist. is needed as well with someone who knows how to play withe carb.
This should get you at least 400 h.p at the flywheel. To get this at the wheels...well thats a different story to many varables. It all depends if you are going to stay 5-speed or go to auto, tight converter or loose converter and which dyno you are going to get on.