Next steps for more power - 318

Just can't leave well enough alone!
My 318 is running GREAT now!
.020" over, stock bottom end
Home porting job on heads
Hughes Whiplash Cam
Doug's D453 Headers
Electronic ignition
Edelbrock 1407 carb

I'm loving the improvements and gonna drive and enjoy it as is for a while...but what would be some horsepower improvements for the future?

I don't want to boost or juice and I don't want to go 340/360.
Ideas for round two?!

Jeff