It's been a over a week now but I'm pretty sure that at an open height of 1.233", there was .020" clearance between all the coils. According to the Haynes book I've referenced you need at least .010" between coils. So the stock 318 springs should be good for .454" lift, maybe even a little more. But I wouldn't push it. The installed height I referenced was 1.687". Note that I didn't use a spring tester.
