Gal60, The "moving around" I speak of is a new, fresh out of the molds block/head will develop internal stresses from the cooling procedure. A block or any other intricate casting will cool at different rates in different sections of the casting, this will develop internal stresses only stress relieving will eliminate or repeated heating and cooling cycles the engine goes thru during it's normal lifespan. No production engine[block] is put thru the stress relieve process except high performance/race blocks such as the 427 FE, these were cast on their own casting line and were stress relieved by controlled cooling over a period of time in a special cooling tunnel dedicated to the 427 blocks only. I would much rather start with a 150K mile 460 say, out of a Lincoln or Merc stationwagon for a good rebuild rather than start with a brand new block. Of course there are exceptions such as the need for a A-460 block that are generally available new only. But for a street type rebuild of a bread and butter 460 IMO the well used core is a better start than a new block. [To add] GAl60, I'd like to address your statement regarding your poor experences with rebuilt engines. Please note that I qualified the subject with a "quality" rebuild" as opposed to the budget production-line "rebuilt" engines. A quality rebuilt engine for a street machine should include but not limited to a align bore/hone, bored and plateau honed cylinders with a plate, square decking and setting piston deck heights, checking lifter bore alignment and some go as far as to check concentricity of the bell housing flange to insure proper alignment to the clutch/flywheel. This accompanies the usual hot tank, baking or chemical cleaning of the block, crank, rods etc. The rods should be reconditioned with lengths equalized, new bolts and the big ends redone. Pistons can need attention before installation as well. New Main, rod and cam bearings with clearances set to whatever specifications the application calls for. As mention above the rotating assembly balanced. The above just covers the short block only, cam, heads, exhaust, intake and supporting hardware will be determined by the application of its intended use. This is where your machine shop should be able to help you make the right choices when purchasing your supporting hardware. When done the pricetag will be far and above that of the budget "rebuilt" production line rebuild.
Last edited by RJP; 01-25-2011 at 07:53 PM.