I know you are suppose to match 1" front with a 3/4" rear sway bar and a 1 1/8" front with a 7/8" rear sway bar. What would happen if you used a 1" front with a 7/8" rear? Anyone know?
sway bars are a tuning aid, there is no hard and fast rule that says you have to use a certain size front bar with a certain size rear bar, in fact a lot of people will not even use a rear bar. it all depends on your driving style and what works best for you and your car.
I think more rear bar equals more understeer? I might have that backwards. I run a 1-1/8" in the front and no bar in the rear, but I am using really stout rear springs. Springs are a big part of the equation.
I installed 4 1/2 Grab-A-Track rear leaf springs from Mustangs Plus with Koni shocks and Caltracs traction bars? Will a 7/8" rear sway bar be too big? I want to use the original mounting places so I am limited on going back with the stock 1/2" that came on my 1970 Mach 1 or go with the aftermarket 7/8" from NPD. Both of these will mount to my original mounting points. My car will have a stroked 351w (393) and the front end will be lightened up a little (alum heads, alum radiator, alum intake, ect..) I am not sure if I should go with the 1 1/8" or 1" front bar.
with the 4.5 leafs and the cal-tracs you'll probably only need the original 1/2" bar if you even need that. i'd install the 1/2" bar and drive it like that for a while and decide if you even need the 7/8" bar. for the front i'd go with the 1" bar. fact is most 1 1/8" bars are made softer so that the actual spring rate of the bar is closer to the rate of the 1" bar so you likely wouldn't notice any difference between them.