Dropping the rear of my 64, what to use.

What do you think of these guys? They say they are heavy duty, but they also say they are stock replacements. These springs arent anything like the ss springs are they? I dont want them if they will bring the car up even higher then the regular springs.

http://cgi.ebay.com/ebaymotors/64-7...023QQitemZ360015343665QQrdZ1QQsspagenameZWD1V