Eddies Vs 915 J's

Ok, so I have a nice mild little 318 in my valiant. it's dyno'd at about 350hp @ 5700RPM

10.2:1 comp
Hydraulic cam 227/242 @ .050. 107lsa. about .480 lift
Performer RPM. 650AVS
Stock 915 J heads with ferrea 2.02/1.6 valves and a 3 angle job
1-3/4" headers

I have a set of bare Edelbrock heads on the shelf. Also a complete six pack setup with new carbs and all the promax tuning stuff

I was looking at setting the heads up with milodon 2.08"/1.6" valves
Maybe get someone to clean up the guides and do a minor amount of port work.

I am also looking at a set of 1.6 roller rockers to bring lift up to the 500 mark.

If I put these on the 318, how much horsepower could I realistically expect to gain..if any?