For about the same price you would have in a reman'ed set of vortec heads you can get a set of Engine Quest (EQ) heads. They are cast in the same plant that cast the Pro Action heads before RHS bought them out and use the same molds as RHS did before they dropped their line of cast iron heads this year. For a mild 350 I would use the 180cc intake runner head. You may could get away with a 200cc runner but you would start to loose low and mid range torque with that size runner on a mild 350 ot 355.
The 270 Magnum by Compcams is a good cam but it is also 30 year old cam profiles. I feel you would be better of using something like the XE274H or if you are going to punch it out anyway Replace the dish tops with a flat top and run the XE284H. If you have it in your budget to upgrade to a retrofit hydrualic roller I have used the XR288HR with very good outcomes. It maybe a little more then you want if you are runnign power steering and power brakes tho.
Also none of these cams will work well with TBI nor will you ever see the potential of a SBC with factory style TBI. Like was mentioned before the RPM air gap is a great instake for mild street engines and the 670 street avenger is a great street carb.
If you are going to bore it .030 over to make a 355 I would strongly suggest upgrading to atleast a Hypereytectic if not a lower end forged piston like the Probe FPS. You can also get rotating assemblies with Hypereutectic and Forged pistons really reasonable now days.
Here is a video link to the 350 I had the XR288HR in. It was a stock LT1 out of a 95 z28 I converted to carb and installed this cam in.