1978 Trans Am Oldsmobile 403 Bottom End

In this video, I bore and hone the block. I also explain the cool KB pistons that ill be putting in them.

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On some bore sizes, it is harder to find performance rings. The Buick 455 had a standard bore of 4.312. +.030 4.342 standard replacement rings may have been easy to find. Specialty performance rings were not easy to find. Some high performance pistons were sold in +.038 to bring the bore to 4.350. 4.350 perfomance rings are easier to find. 4.350 might not be a nominal size. The Chrysler 440 had a standard bore of 4.320 and +.030 pistons were common. Given how much the 440 outsold the Buick 455, I can visualize why performance ring companies would be more interested in making 4.350 rings. There may be more people interested in a better General Lee than a Smokey And The Bandit. This may be why the Olds 455 has performance pistons in +.024. There may be more interest in building performance 4.375 rings instead of 4.381 rings for the same reason there may be more interest in building 4.350 rings instead of +4.342 rings. This can be why your piston may have a 1/16x1/16x3/16 ring pack. There could be enough interest in making special rings that size. I also like that the Keith Black replacement has a heart shaped dish. A better quench area can lead to more power without more smog. It is said that it might also tolerate octane better.