When I built my car, I wasn't able to find redline tires in the size I needed. I found a website that sells stickers to add them yourself. They are made out of rubber and you attach them with adhesive that permanently bonds them to the tire. The tires I chose were Ohtsu, they were cheap, came in the size I needed, and had no lettering on them that could be seen from a distance. Something else they had was a bare stripe all the way around that made a perfect spot for gluing the redline on. Most blackwall tires don't have a spot all the way around. I used the inside ridge of that bare stripe as a guide for gluing down the redline, it worked out perfectly. I was apprehensive about how they might turn out, I didn't want them to look cheesy. I didn't even want people to notice they were added. Now that I have one tire done I can say they look great.