175 x 70 x 13 tyres!
You should have done your homework first & saved yourself some grief.
I have used 185 x 60 x 13 on 5" rims for the first few years, then on 5-1/2" rims for at least the last 20 years on a succession of Datsuns including a 1200 ute & two 1000 models, including my lowered sedan. The same 5\1/2" mags are going on my 1000 coupe shortly.

You gotta keep the outside diameter of the tyre as close to the original tyre as possible to avoid rubbing on the inner guard.
It is also critical that the wheel offset be within reasonable limits, otherwise you will get the problems that you are now experiencing.

Please note, wheel offset & wheel backspace are NOT the same thing. I suggest that you see a large[ish] tyre dealer & ask if he has a copy of the "Tyre & Rim Association" Standards Manual. This book will have a clear description of wheel offset & it lists all the industry standard specs for just about all tyres made since WW2. My copy is dated 1988, and does not list many of the contemporary 17" & up sizes, but i don't use them, so it's still relevant for me.

The outside diameter that you should be looking for, to use on your FRONT wheels should be close to 550mm.
Your 175 x70 tyres are 576mm in diameter & this extra inch [25mm] combined with what i suspect are the wrong offset wheels are very likely to be the cause of your problem.

Hint. Do the homework BEFORE you spend the money.
Chris
PS 185 x 60 x 14 is nominally 578mm in diameter for highway type tyres.
Modifying the body for clearance simply means that you got it horribly wrong in the first place, but rolling the lip up is a recomended practice as it actually strengthens the edge, but roll it, don't bash it. Try to fill the hollow cavity with some windscreen sealant to keep out the mud which leads to heartbreaking rust.