Though my car is 10 years older, same difference. I started out with 3" blocks & the original 70+ year old sagging springs. Was fairly low, but the scrub line was below the rim & ran it this way for a couple years. Then I bit the bullet & bought a pair of Posie's 3" lowered rear leaf springs & it was a bit higher than with the 3" blocks and old springs. I removed a couple leafs....still not low enough for my taste, so I cut my 3" blocks down to 1" and installed those. It's about as low as I can go without bottoming out on the stops or going with a "C" notch (maybe in the future). My front has parallel leafs also & I was just going to remove a couple leafs from the stock set-up, but 1 of the eyes was broken off, so ended up having a spring shop make up a set, slightly lowered, which ended up in a slight taildragger stance (which I like a lot), but I wanted the front a little lower, so I removed a couple leafs & this is where I'm at now.
**EDIT** Here's a link to a thread I forgot about....should help a little:http://p15-d24.com/topic/33585-new-ways-to-lower-the-rear-end/