RH1 or RH6 for my 1972 750

I need to fit a new head to my 1972 750 commando and wanted to know if folks thought the RH6 was better in terms of casting and machining and therefore more reliable? I know the RH1 was standard on my 1972 and lower compression I’m just interested to know which head people would recommend...I’m also aware that the RH6 was fitted to 1973 commandos but my bike is already a bit of a mix..thanks in advance

Take the mintest head you can find .

Tapering from 32 down the throat to 30 , can , amoust other things , be beneficial .
The Stok intakes are somewhat curved , creating a kink , almost . In the induction .

Whatever , set up carefully , the olde 40 thou of coilbound at TDC being ascetaied .
THEN , a hot cam the hights differant for the same issue . Whatever - Quality valve springs are adviseable .

Any recessing / pocketing in the valve seats means shadowed lift and efficiency lost .
So a good original head with NEW lead free valve seats , high n proud .
Would be way better value than a used head with sunken seats .

The back face ( stem side ) should be flush with the chamber face .
Plenty of people have paid plenty of money to monkeys for ruining there slightly worn but unwrecked heads .
So a low time replacement , or expert competant engineering are in order . Norvil Springs were W&S , same as Johnson Motors TRiumph
from back when Noah was a boy and Triumph held the L S R for 15 years or so .

ARGHH ! POLISHING the snot out of the Cam Follower faces ,
perhaps just REFACING them, ( oil retention )
and mirror polishing Cam Lobes , will help life there too . And Spacers not Thackery Springs on the Rocker Shafts .

Hi Mic

Your question is casting reliability difference between RH1 and RH6 heads. I’ve had both and they were equally reliable as far as oil retention, valve seats...etc. If you have a combat cam remaining in your ‘72 750 I would go with the RH6. If standard Commando cam then RH1.