Can you post a picture of how everything sits with the 350lb spring? I am not sure if you mean that the lower control arm is pointed down or up right now.
If it is pointed down (the ball joint is lower than the bushing) you can probably fix it by carefully cutting it down. If you don't want to cut it, you can get a softer spring but be aware that will make the whole front end softer. Whether or not that is a good thing is up to your personal preference.
If it is pointed up (the ball joint is higher than the bushing) then you need either a longer or stiffer spring.
Your originals were 375lb, but you noted that they were installed incorrectly so it is hard to say what it would have looked like with that spring rate.
