Small block 273 920 head porting services.
Contact GTXJohn on the forum I know he has a few sets of 302's and he might be willing to part with a set. Also get him to do the valve job too although I'm not sure if the flow he gets which he's stated was around 200 cf is with a stock 1.78 valve.
200 cfm is more than enough for what you want.
You wont need to port them.