I don't think I can really go too wrong here. Just picked up the Greyhound 5.5HP engine at Harbor Freight for $79.99+tax. It was marked down from $129.99 to $99.99, and I had a 20% off coupon making the final price $79.99 Aluminum block with a cast iron sleeve according to the box. It matches the dimensions of the crankshaft of the B&S 12V8xx engine it will replace that is 10 years old +/- a year. http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=96156 Since I got it at the store, no shipping charges. I supposed I could have guilted oilBabe into a new lawn mower since we just dropped $4K on furniture today, not to mention her car last week. But I might need a second job cutting grass to pay for all the goodies. Anyway, I'm hoping this experiment works out well. I may tear down the old engine and have my daughter rebuild it with me, just so she knows how this stuff works.