Since we're reviving an old thread, the McCoy springs that Man-a-fre and JTO sells are
crap. Numerous people have had problems with these springs, and retailers aren't really that helpful. Mine have sagged back to about 1" of lift, and that includes some add-a-leafs. :mad3:
Custom springs that Alcan sells are worth the money, but make sure you have the shackle end built about 1" longer, otherwise tell them what you want and they'll build it.
The only stock off the shelf spring I'd recommend are Beltons. Cheaper than OME, and the quality is up there. Super adjustable too. The rear spring is ten leaves, 9 are 6mm thick, and an overload.
From Prairie Dog Parts (a wholesaler in Canada)
They are made with grade 10 springs steel, the factory is ISO9001 certified so the quality is very consistent, they are fully scragged and shot peened like EMU's, so they won't sag for a good long time. A really good leaf. The refinements that EMU's have on them is the 'flat spot', tapped ends, and the teflon sliders between the leaves. That's really the only difference. And price! Price is the difference!
http://www.prairiedogparts.com/ - the only wholesaler I know, can put you in touch with a resaler near you.
No affil. But I have bastardized stock 55 springs, worn out my McCoys, bought a set of custom alcans, and ridden in a few Belton equipped trucks.
EDIT: You'd be better off just buying another pair of 55 springs, although they're kinda rare in Canada.