The part # I have is 930-355-011-03 and when I did a search I found it on pelican parts which is where I bought it
http://www.pelicanparts.com/cgi-bin/...911%20(1978-89)
As an update to my previous statements, I can lock up the front tires first with staggered rims and street tires. But when I toss on the race rubber it throws you against the belts and stops the car incredibly fast with hardly a peep from the tires.