I have Firestone 2600s in my full size right now.. and i bought re8s and they would be fun to make fit. I'm not gonna attempt it because it looks like it would take alot of structural integrity out of the frame.. can be done but it wont be easy.
but the 2600 rides fine? no problems as far as lifting the only thing im worried about is the weight of the motor and it taking alot of pressure to lift
re 7 will be good bro i got a 95 fullsize with a 454 and its on 2600 stones in the front and it lifts it fine,im running straight bottle,at 200 psi hope that helps