stick with the 302 and rebuild it like you had planned. if your only wanting about 350-400 hp then the 302 will do just fine and will keep the weight on the front end down. if your going to buy a .030 rebuild kit, go ahead and get for a 331 or 347. it will be more exspensive but it WILL get you the power you want and more. make sure that all the machine work and cam bearings are done at a reputable machine shop, oh and freeze plugs too. the rest is really not that difficult, just make sure you get a hanes or chiltons manual and follow all the tourqe specs. if you dont have a torque wrench the buy one, you cant do the job witout one and its great to have around. as far as the tranny, a c4 will hook right up with no problems and will hold up to the horse power your looking for. just remember that a c4 only has three gears so if you plan on running done the highway, your going to be running higher rpms which overall means shorter engine life. with the intake i would probably stick with a dual plane unless the kit that you buy is made for really high rpms and then you have to make sure you match a cam with the intake. its very important to do this because if you dont your engine will not be able to live up to its potential. if you want to keep the car streetable, stick with the dual plane intake and a mid range rpm level and go with 3:73 or 4:10 gears for the rearend, this combonation will still give you a **** of a jump off the line and then when the rpms get into there range, you'll really be able to take off. porting the heads will work good, but if you can find an old set of 289 heads you would be able to pull out even more horsepower. those stock heads have a 64 cc combustion chamber and the 289's have about a 54-56 cc chamber. that calculates into more hp. let me know if you have anymore questions.