Post
by budmspeeco » Tue Feb 16, 2010 9:20 am
You started at the wrong end to verify your correct/incorrect (?) bore. Measure the pistons FIRST, add that to the manufacturers recommendation of clearances for the pistons SECOND, then measure the bore in your block THIRD. The first two numbers added together should be the third number, bore size, +/- .0005. Ring gaps should also be to mfg. specs. I have found the ring packs have begun to be installed with slightly larger gaps the last few years. I can guess this is due to the improved materials being used, because of less wear after the initial break-in period. Even skinnier rings lasting 100,000 miles is now almost a given. Your ring gap a few years ago would have been about .017. If your original measurement of the ring gap was in the .021 range I would suspect the bore was correct. If the block was over by the numbers you gave, .0065, gap would have increased to approx. .0507. A .001 increase in a 4" bore motor will give a .006 increase in bore diameter !! I hate to say this, but a lot of "hemi" guys on this site tend to "overthink" everything associated with a "hemi" motor. It is just that, a motor. Rod/stroke length debates in the 392 section come to mind. Pistons first ,then boring and decking another. Do the math, then worry !!! Buddy
'48 anglia