340 buildup

Hi all, I am building a 340 for my T/A and would like a little advice. The car is # matching engine and trans (auto), 3.90 rear. I am thinking of bagging the current motor and building a fresh smallblock as to preserve the original. I want a car that runs on pump gas, will idle (lumpy ok) in traffic without getting hot, has enough vacume so the brakes will work and go like he**! I want a respectable mid to low 13 sec. combo that may see the track a few times a year, mostly a hot street car and retain the 6-pak setup. I am thinking of a stroker, alum heads, headders, looser converter ok. Do you guys have a reliable recipe? I am thinking of changing the rear to 3.55 as it is such a bummer to go down the freeway tacking 3k+ at 60 mph so I am thinking a torque combo would probably be best. Please give me as specific details as you can (cam specs, piston cr, head cc/valve size, headder tube etc)Thanks!!