Quote:
Originally Posted by pontiacmark
I have a 69 and 72 400 block that are standard bore that were running good when pulled.. I asked a machine shop for quotes on cleaning, boring, decking, freeze plug and cam bearing install. The shop also quoted align hone of the mains and sonic checking. Aside from simply being thorough, how necessary is align honing and sonic checking of a known street engine that would be bored .030 over?
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Do you X-ray vision? All an ultrasonic inspection will do is confirm there is enough material in the primary thrust face to machine out. Blocks corrode internally; they also suffer from coolant erosion and cavitation. I know of two ‘66 389 blocks that had primary thrust face cylinder walls that were less than .090 thick. The MINIMUM primary thrust face cylinder wall SHOULD be .150-.180. Align honing simply insures that the main saddle alignment is correct. It’s a simple process that removes a modicum of material from the main caps and the main saddle. At most, .003-.005 out of the caps and .001-.003 out of the main saddle. Iron DOES distort over forty years of heating and cooling cycles. Have them check the cam bore alignment as well.