5.3 or ls 1 heads

[67txcamaro]

I have 5.3 862 heads and I am thinking of going with ls 1 heads from a 2000 camaro (as of tonight i dont know the casting number)
my understanding that they both have

Intake Port Volume: 200cc
Exhaust Port Volume: 70cc

and the difference is Combustion Chamber Volume:

66.67cc ls 1
61.15cc 5.3

going with a texas-speed torquer v2 cam with a 3200 stall 4l60e
232/234 .595"/.598" Camshaft

what are your thoughts? should i stay with the 5.3 or ls 1?

I know i have to mill the ls 1 heads. The machine shop is saying .35 but i have read .45. what should it be?

this 1967 camaro will be a drive on the weekends kind of car and maybe a couple of passes down the track and maybe a lil bet of nos down the road, but mainly a drive around car and look cool and sound cool.

this is first project in my life (damn you tube made it look easy hehehe)
now to deep into project to stop now.
thank you for your help.