What would you do?
Did you sonic that bore, or others? .006 is more movement (almost double) than I have ever seen....might be a very thin block negating use?
I'd have to agree with this. I have never seen a wear pattern that looked like that. I used to build engines with virgin blocks from known good running engines. If someone "rebuilt" it I was not interested. When I got serious, I got a Sunnen hone and would hone just enough to clean up a bore, with torque plate and mains torqued to spec. Sometimes I'd run stock size pistons if the bore would clean up round and straight. Very interesting what you could see, high spots, and wear patterns. Glad you bailed on that block.
In reply to your original 2 questions: I always use torque plates on everything I build. I have plates for SBM, BBM, 2.0 Neon, and Early Chrysler Hemi. I had plates made for SBF and Desoto Hemi. I sold my SBC plate years ago as I was not interested in building them anymore. Only the SBC paid for itself, maybe the SBM also. I just will not build an engine without torque plates.
Balance is in the same category. I balance everything, pressure plates, flywheels, driveshafts, brake rotors, brake drums. Vibration drives me crazy. Imagine if you cruised down the road at 80 mph and everything was smooth as silk... No chasing crazy vibrations and the extra wear they cause.
If done right, a good engine will last forever with good maintenance. The extra machining cost over decades easily pays for itself. The side benefit is your engine starts before it makes one revolution, is more efficient and makes more power.
