68 Buick GS California, biggest rear Wheel /tire combination?

Hi guys

i have this thread going on over at the PRO TOURING section..
and i got recommended to post it here as well.

http://www.v8buick.com/showthread.php?301825-15x10-on-a-68-GS&p=2500484&posted=1#post2500484

Im looking for a
agressive look on a 68 GS 350.

whats the biggest rear tire/Wheel combination possible..

lets say standart 15" rallys (8" or can i go 10"?)


further
what tire / wheel combo would i need
if i would go

all around 17"

rear 18" front 17"

?

anybody got picks of there setup??

 

PS:
i dont mind lifting the rear a bit with coil spacers for example to create space...
i like the Oldschool look as well

 

275/60/15 on a 15 X 7 Rallye...unless you want to start modifying things.

 

I’ve run a 15x8 wheel vintiques with a 26x9 slick, and seen that same wheel with 255/60s on it. The slicks are bulgy and barely touch the fender trim when turning hard (onto the return road).
Patrick