I think 20 hp can be gained just by tuning.
Start with the carb.
I know it seems too big but maybe the secondaries can be adjusted to open later. Finding the optimal fuel air ratio will help. So a good AFR gauge will be a big help.
Get the distributor tuned.
Try different carb spacers.
Try a set of 1.7 rocker arms.
You can also try changing the camshaft timing with an adjustable timing set. I think it would respond well to being a few degrees retarded. But might also hurt the overall peak rpm.
I don’t think the cam is a horrible choice. Very similar profile to what I’m using although mine has more duration and lift on the exhaust side. Which is generally preferred for a SBF.
The OP could try only getting 1.7 rockers for the exhaust only. This would also increase the duration and lift of the exhaust valves.
1970 Mustang coupe