I believe that the problem is the aluminum A Arms..thats the reason for not strapping to them.
S-Line in Texas has basket tie downs and also made me a custom set. Rich Lacey, who brought our cars to Detroit for us, had some nice baskets that worked really really well. His website is
www.rct1966.com you might send him an email and see where he got them.
I have seen several people that in a crunch tie them down with criss cross through the rims but you run the risk of scratching the rims.
This also goes back to doing a dyno pull on the car...you must take the pans off to get to the frame in order to tie it down to the Dyno...unless someone has a different way which I am open to hear.
matt