What will my 68 Dart 408 run in 1/4 mile?

Try them tubleless first. You may be pleasantly surprised. I run MT sportsman pros tubeless all the time and have for years. One time I had one tire needed to be tubed.

How often do you have to fill them up? They Sportsman Pro's are on there way and I'll be running them tubeless (or at least I'll try).