[olehead]

This post is just for information based on my experience - I ran at the track all last summer with a combination of Radial Front tires and Hoosier Quick time pros Bias Ply on 15inch Dark Star Rears. Here is what I learned:
1. If you decide to do this you must run you Hoosier tires at a higher PSI - ran mine at 18
2. Your car will tend to float once you hit over 90mph and can get a little unstable at the back end
3. You will need to go around the water and then back in to burn out or your front tires will leave water
4. I still managed a 11.72 with this set up but that was a interesting ride!!
In closing the only reason I kept the front raidials is too lazy to change 4 tires but I have order skinnies for this year - Hope this helps for those making choices - Oh Bias Plys are a must for manual!!

 

[olehead]

I forgot to add one thing to the this post. The warmer the weather and the better the track prep the less the impact you will having running the mix - but if it cold and the track is slippery be prepared to have a handfull -

 

[93mustang]

I run Hoosier Quick Time Pros 26x9.5 (15 psi) on 15x8 Weld Wheels. And BFG radials on front. Never had any problems. I am not going that fast though. Low 13's at 104 mph. Never had a problem.
From all that I have read, you can mix radial and biased front and back, but not side to side