It's easy. I built my motor and i'm running almost 500 HP, if not 500 at the crank and i'm using a pair of GM heads, ported the **** out, but still GM heads.
Start with the cam, get an entire matching valvetrain set of comp or lunati cams, pull the heads and do a cheap port job, and or fit them with the 2.02's. You can prolly get away with keeping the stock carb, or just pickup a nice cheaper rebuilt holley from summit.
And get a nice aluminum intake, and port match it to the heads, you can do that yourself with a dye grinder. If you want to go the extra mile, get a mallory or MSD HEI dist, and a cheap pair of headers, then wrap them. And you'll make an easy 300-350 without slashin the milage, and you'll handle heat alittle better.
make sure you get a cam that your heads can handle.