My engine rebuild is going great. Not too much wear or damage to the engine, which I attribute to Mobil 1. Cam shafts look virtually new! #3 and #5 cylinder did suffer damage. Small chunks broke off due to old age. Another customer at the shop told me my damaged pistons were caused by lean mixture because I was not using a converter. He said the ECU needs to "see" a converter because it's adjusting for the backpressure. I have heard this before. I do have a Dinan Chip and cam gear (Euro headers waiting patiently to be installed too!) and I would think the chip took care of the lean issues. The engine did last 250,000+ miles before this damage so I really don't think his diagnosis had any merit. So, the solution I feel is get a cat that will blow in few thousand miles or get a Euro muffler w/ more back pressure. My head hurts and I just don't know who to belive anymore! Any suggestions?