They do give you three or so extra links to get everything hooked up and held together while you take up the slack and then are able to advance link by link.
No store blade for right now as I had two 42" long pieces of 1"x14" yellow pine. and least I think that it is yellow pine. They came from some old school bleachers and are very tough allowing some give with some serious weight on them.
Wood for a plow?...Yes, it has the weight and strenght that the light metal Sears blade does not possess. When I looked at the Sears blade, It almost seemed like something you could make out of a cut in half trash drum.
I have some heavy guage sheet metal on the front side of those two pieces of 1"x14" wood which are bonded together with glue and screws. They are reinforced even more by those twelve carriage bolts that run straight through and are bolted to floor flanges on the back side. I have 3/4" galvanized piping threaded into those three floor flanges and they are then held to the frame arms via "U" bolts that allow the pipe to swivel for raising the blade. The frame arms came from a street sign that the DOT gave me after a motorist decided to run it down. This is 2" square tube steel and is very strong.
The whole "blade" project cost me $0.89 per pound for hardware (just bolts and nuts) as everything else was on hand or free scrap. Paint is needed on exposed metal and wood. It works great but I have only used it once. I did have to pay for those wheel weights and chains but was armed with the part numbers when I entered the store which saved them a lot of work. After some polite haggling, they gave me the Internet Price which is often 15% less than store price.