OPINIONS: 400 sbc top end upgrade

[xxblade31]

Hi all
Looking for some help upgrading my existing 400 gm 330817
My engine runs good and looks to be rebuilt a while ago. but wanted to put on some new heads and maybe a cam for some more punch.
What I can tell: headers 3 inch exhaust, performer intake, Iron heads
Holley single pumper, small cam

Any combo recommendations would be appreciated.

Another Idea
Cost wise it maybe cheaper instead of a complete rebuilding the 400 just buying a 383 pre built motor. thoughts on that would be awesome too.