Hopefully Van will chime in (hi Van!).
I have seen some of the cars run Avon Bias Ply tires.
I think I have seen others run Hoosiers but I cannot remember whether those were radials or bias plys.
I will check some photos of Nearburg's 935 I took at an RR at Laguna.
Roger Kraus and his son are old friends and their biz is about 20 min from where I live. I think that they still sell Hoosier and Avon.
See below for Avon:
