toyota 22R valves are rumored to work for the G ; I have one exh valve here I will send if you want ; it was about 8$ and is slightly O/S ; it has a SS head ; do a search on the Induction forum there are several threads about the Toy valves (a cheap O/S valve for the G, altho not the swirl, DAMHIK,IJK)
when you get new or used valves you may have to have a machine shop install them to match the seat, or you may be able to just 'lap' them in depending if ur replacing a stock with stock (more likely to just need a good "lapping")
if you put an O/S valve in there you will likely have to pay for the valve job ; IMHO the 36.8 mm exh valves are a good performance upgrade; my shop was able to put them on my stock seats