any benefit to swapping heads?

sure- look for some 3:91s if this is not a daily driver it's a mechanical change- you can calculate the difference- and then drive and pretend where your new shift points would be
but for the cost of gears you could replace the high compression bracket racer with headers cam you have with something appropriate
advancing the cam 6 degrees works getting the intake closed earlier but does nothing about overlap and hurts your power expansion on the combustion stroke and gas mileage, if that's a concern
That said do a compression check and try it and do another compression check
you can then calculate your intake closing points and see where you want to go
how's the top end, passing etc now?