Cams for 318's

I had some questions about cams and this thread seemed like a good place to post instead of making a new one.

I'm new to mopars and old cars in general. I'm used to DOHC motors where replacing heads and cams are almost never done due the cost and complexity, so I know next to nothing about cams except what I have been able to glean from some good posts in this thread.

I have a 1978 318 la. It came with a 650 CFM 4 barrel carburetor which is overkill for a stock 318. It doesn't appear that anything else was done to it, except the heads were removed at some point, because there is head gasket poking out a little, and it clearly is not a 1978 era head gasket. But, it did come with the stock exhaust manifolds which is why I saw I doubt any other performance parts were added. I think the previous owners just had the 4 barrel carb laying around and used it to get the vehicle moving.

Is there any street able cam that can take advantage of that carb without swapping the heads? I've already installed headers. 1 5/8" primaries into 3" collectors.

I probably wouldn't be asking, but the horsepower stock is less than my Wife's VW, so I'd like a little more. And, I'm already planning to replace springs, lifters, etc. Any help is much appreciated.