My new to me 04 gt sits an inch high in the front. Car is pretty level side to side but front measures an inch higher. Tires are same height. New shocks all around it. Can I use lowering springs just on the front with no bad consequences?
Assuming you have stock springs - lowering the front will likely always be a stiffer spring as well. This will result in more understeer which can be unnerving with spirited driving.
Thanks for the info. I'm just looking to level the car and I see one can get one inch lowering springs for the front. This should level the car. Will this still produce the under steering?
The height is not the issue for understeer I mentioned. If you have stock size tires/wheels and stock suspension - Stock height from floor to fender should be: 27.5" front, 28.25" rear. If your height is different than this you have worn isolators, aftermarket springs already, or your car might have been wrecked.
The spring rate is the issue for adjusting understeer/oversteer. Lowering springs are stiffer than stock 420 lb/in in the front. The car would drive fine on the street if you just drop the front.
But for $100 extra you could buy a complete front and rear set that complements each other for a better balanced car. I would spent the $100 extra and replace the front and rear springs with a set that provides the drop / stiffness / type (progressive vs linear) that you want. https://www.americanmuscle.com/99-04-mustang-springs.html#shop-by1
I would get a set of cc plates while you are lowering your car.