advice on heads

Thanks guys for the info you all have given. I have read each one of the responses and with all the different angles and ways I can go it seems like each way presents more changes to be made so I think I am going to just have these J heads worked and have him do as much as he can to give me as much as he can and leave it at that. I bought this motor that was sitting for a period of time out of the vehicle because Tyler wanted to just drive his car after we finished the restoration. We had a couple of 340's sitting here at the time and had planned on eventually of building one. But he wanted to drive it now. I couldn't blame him so I bought the engine and tore it down and honed the cylinders and put rings and bearings in it. There was no ring wear what so ever on the engine. Had only about 30.000 miles on it. I told him then he didn't have a fast car and he didn't care. He saved a lot of green and got to drive his classic. Now he would like to have a little more power. I don't know exactly how much he will pick up with the cam and heads but he should be happy. This guy has a dyno at his shop and I plan on putting it on there when its done. But with all I have been through lately with the heart operation, I want something simple for now. Maybe later we can put a crate engine in the car if he wants. But thanks for the help. Bill