Why can't you just change out your gears at the track?
I thought people used to do this all the time.
I have a set of 4.57's and a set of 3.23's for my 8 3/4. When I put them in my 66 B'cuda I plan to drive to the track with the 3.23's and change the chunk to the 4.57's until I can save for an enclosed trailer.
I might make a mount also in my trunk for that extra pig just over that passenger rear tire?
A little extra traction never hurt anybody and it would definately be the least expensive route. :-D