Suspension Anyone know if a stiffer rear shock will eliminate too much rear end travel?

Stiffer rear shocks add oversteer. If you stiffen up your rear shocks, you will have less rear end grip than your previous setup. That will negate the benefits of having a wider tire.

Limiting suspension travel will make your car handle worse when it comes to cornering. As an example, I use Tokico Illumina 5-way adjustable shocks & struts on my 1992 GT autocross car. 5 is the stiffest setting. I have my shocks & struts set at 2 F and 2 R. That car runs 245/40/18 tires and has beaten cars running wider tires on an autocross course. With a stock-style (non coil-over) suspension, going too low or too stiff with the springs, shocks & struts will make our cars handle worse. Also, a staggered setup adds understeer to a car that already has understeer from the factory. If this is for a performance driving application, a square setup will perform better.

Stiffer shocks will not reduce the range of your suspension travel. They will make it ride rougher and maybe reduce the speed of the hits and number of times the tires hit the fender lip. But it will still make contact. (Warhorse says why else this is a bad idea.)

Jacking up the rear and adding taller suspension bumpers (or air shocks) 1970’s style will put the lower control arms at a not parallel to the ground angle. That leads to axle tramp on these cars. So wheel hop is more likely to offset your traction and break parts.

Rolling the lips of the fenders is possible if you are determined on running these tires and wheels.

I rolled the lip on the wheel wells of mine. Gives you clearance and doesn’t mess with the suspension.