Just fitted new springs

Depends on the "free length" vs the "compressed length" as to whether it holds tight in the strut when in the air...  If using normal springs then you either live with it or (see below) or with coil overs you can get "keeper springs" of a low poundage to keep them taught but not effect the normal spring rates... (GDub has done this - not sure he fitted the keepers yet though)
 
I have had standard struts with lowered springs that turn when raised off the ground, but providing you "reset" them correctly in the seats before you drop it back on the ground then no issues....
 
Only issue is if they are that loose they can fall out that you have to worry.  I have one set of lowered springs that I have had to use strong hose clamps (not el-cheapies) to to hold the springs in so they cannot fall out if I get a little "air".....

So finished the job on the other side today, the cars 1" higher than it was! when you put the springs side by side the old ones are 2" longer? Thats some serious sagging been going on. There's no point in fitting the lower blocks now the car will look ridiculous. 
 

A 2lt front spring in a Kent engined car will also raise it around an inch from a pinto engined car too....