Thanks for all the info! Yes I do need to pick up all those other items, I was first concerned with picking up some heads. Pistons are next on the list. I have a 67 el Camino that I know very little about, besides that it has a turbo 350 trans swapped in and the engine is the original small journal 327, which is why I’m pulling it to keep it on the side. It’s goal is to be a fun street car around 350-400hp and 400tq. The engine I picked up is a 1996 TBI 350 with a hydraulic roller cam, the heads in it seems to be swirl ports which I heard are no good.Is this a complete new build?
You need to also pick out pistons so that the compression ratio is what you want. For example, if you use stock budget GM 350 crate engine pistons, and buy 64cc heads, the best compression you will get is about 9.0-9.2. This is great for running on regular pump gas. However, swapping in some flat top pistons would get you more compression, and domed pistons an every bigger increase.
Once you get the heads figured out, we need the weight of the vehicle, rear end gear ratio, transmission model, torque converter stall speed, tire size, etc. Then you can ask for a recommendation for a cam. don’t pick a big thumper cam first, and then try to get everything else to work with it. The cam comes last.