Sorry to ask a Camaro wheel question, but I'm at work and my employer slaps my hand when I try to go to Camaro.net.
I'm looking at buying some XG code 14x6 rallyes that came stock on 68 Camaro SS 396 (at least according to the seller). I'm wondering if they will fit my 68 Camaro which has been converted to front disc brakes taken from a 72 Monte Carlo.
I appreciate any insight.

XG's are disc brake wheels, so, yes, they will fit. I have two of these rims sitting around the basement, and I seem to recall having them on the front of a disc brake Chevelle for a while.

Great. What would be the biggest tire I could put on them? I have 4 pretty good but very old Goodyear Arrivas on my 68 now that I might put on the Ralleys. I don't recall their width but if I can go bigger I might.

I have seen people use a 235/60R14 on a 6" wheel, but I believe this is pushing the limits a bit.

I ran 215/70R14's on my '70 Nova w/ 14x6 rims... seemed to be a good combo. I think 215/70R14 is roughly equivilent to the F70-14 size that came on Chevelles in 69-70 period. If these fit my '70 Nova well, I have no doubt they will work OK on a Camaro.