The first thing that I bought was an engine. Jalopnik had a gret guide on how to build an LS engine on a budget, so I decided to go that route. I first picked up an LM4 aluminum block from a 2004 Envoy XL. The guy at the scrap yard said that it was tested and had great compression, so I couldn't pass it up for the price.
I spent the following week tearing it apart and cleaning. The engine looked good, but it did have some rust. I managed to snap a couple of exhaust manifold bolts which was a major pain (you can see more pics on the blog)
I got a whole bunch of NPT fittings from my dad and put together a leakdown tester to see how good the engine internals were. To my surprise it pretty much had 0 compression. You could hear the air rushing out pretty much everywhere. At this point I decided to take off the heads and clean up the valves to see if that would solve the problem.
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