Jeff Smith: So that makes you a junior in high school, Rob? It's great to hear from younger guys who are into car crafting. You've chosen a great car as your first project, and I think we can help. The biggest issue is managing all the details involved in stuffing a V-8 in place of the inline-six. To begin with, you're going to need V-8 frame mounts and motor mounts just to bolt the engine in. The rear trans position is the same as the Powerglide, and the driveshaft length should also be the same since the Powerglide and TH350 are the same length. If you're going to reuse the Camaro exhaust manifolds, they will work, but it will require an all-new exhaust system. We found a complete single crossflow muffler system in the Classic Industries catalog for $339.95, or you could go with a Flowmaster PN 17104 crossflow system for $369.95. There are certainly other kits that would also work; these are just two examples. The Flowmaster system will be dramatically louder with that distinctive Flow-master resonance, which you might like.
The original six-cylinder radiator will probably not be sufficient for the larger 350 engine, so a new or at least good used radiator will be necessary. Hopefully the small-block came with a complete accessory drive, meaning all the pulleys, brackets, and other components needed to perform the installation. Keep in mind that you'll also need new radiator hoses, heater hoses, clamps, belts, coolant, and a whole bunch of other stuff to complete the engine swap. These little parts are what will drive up the cost of the engine swap. It's entirely possible to spend over $200 just on small items like thermostats and heater hose nipples for the intake manifold and other seemingly insignificant parts. If you're lucky, you can reuse the transmission cooler lines from the original Powerglide since they are similar. That will save you some bucks. Don't forget that the new radiator will need to be configured with an automatic-transmission cooler. Don't try to run the car without a trans cooler.
If the engine has been sitting for a long time, it would be a good idea to pull all the spark plugs out, squirt engine oil into all the cylinders, and turn the engine over by hand several times to help keep everything lubricated. Drain and replace the oil and filter. You might even want to pull the distributor and pressure-lube the engine before firing it. We just did a short story last month in the November issue on how to stab a distributor, if you have never done this before. Use some kind of dummy distributor body to ensure that both sides of the engine get oil up to the rockers. The best move would be to add new plugs and spiral-wrapped plug wires. You will also need to come up with a switched 12-volt power source for the HEI distributor since the early Novas used a resistor wire in the harness to feed power to the coil. The original resistor wire only allows about 5 volts, which won't work well with the HEI. Instead, find a switched 12-volt power source off the fuse box.
As for the intake manifold question, the Edelbrock Performer RPM is a great manifold. I would go with that over the stocker and look for a good used Holley 600-cfm carburetor. The 0-1850 Holley 600-cfm vacuum-secondary is a decent carb and should be easy to find. The part number is located on the driver side of the choke housing. You'll also need to change the throttle linkage to make it work for a V-8.
I'm sure I've probably overlooked one or two parts to this swap, and we haven't even talked about adding stiffer front springs to compensate for the heavier small-block, but that can come later after you get the car running. Good luck.