Determine your budget first. Cleveland heads are an interesting subject.
Your cam a 226/236 112/+5...about as aggressive as I'd want to go for a street 357. The exhaust is a little big, and Crane specs it as a forced induction cam (there for the big exhaust). However, that probably doesn't hurt much.
Tappet lift is .314 intake and .325 exhaust. However, your Cleveland should have 1.73 rockers, not 1.6. That is .545 intake lift, and .563 exhaust.
Net, there are better cam profiles, but not a big issue.
Cleveland heads where pretty advanced for 1970, with big canted valves and big ports. They are pretty mediocre by contemporary standards. However, some of the best aftermarket heads are for Clevelands and Clevors.
This includes the Engine Master Challenge winning
CHI heads from Australia. For your combo, their smallest 185cc would probably be best. You will need their intake also. With shipping (from a US distributor such as Porting Dynamics) your probably looking at $2700 or so.
When assembling, you need to watch the compression ratio. You didn't indicate your deck height or gasket thickness. With a carb, I guess you are looking at 10:1 to be safe. And you would like to keep the quench to around.040. With the dimensions, the head distributor can mill it to get the right chamber volume. You will need to measure the intake and exhaust pushrod lengths after assembly and order the correct length ones.
Since it is a Cleveland replacement head, I believe your exhaust manifolds should line up fine.
As was indicated, you probably have 300hp or so already. This may take you closer to 400hp. More is possible with a cam change. However with a carb and nothing to detect detonaton and pull timing, you are not going to get the 450-500 rear wheel horsepower some 347 LS1 Chevies get on pump gas.
One note on camshafts. Most of the catalog cams are flat tappet designs. It sounds like a hydraulic roller would be a good selection here. Comp can make a custom setup with their XFI lobes that would work well. Since there is no emissions issues here, you could tighten the lsa and end up with something like a 224/228 110/+4.