At the beginning of any complete engine buildup, the block needs to be cleaned. Serious engine-builders know that hot tanking, block machining, and a host of other engine-building tasks all require the block to be stripped first. To do that all of the block’s plugs must be removed (even with a new engine) to allow cleaning access to areas that allow oil or coolant to flow. But did you know that the typical Chevrolet V-8 contains not only a set of expansion plugs, but also a variety of other plugs in some hidden areas? Leave one of these small plugs out or install one improperly, and your new engine could fail during the first few minutes of break-in. To make sure that doesn’t happen, we’ve compiled some information showing just what to look for during your next block-rebuilding excursion.

The typical block-plug kit found in most auto parts stores is not complete for a thorough rebuild. It’s usually missing several ½-inch expansion plugs and ¼-inch NPT pipe plugs. Sometimes two kits will be sufficient to replace all the plugs in your block. Remember also that many 400 small-blocks had one additional freeze plug on each side, totaling 10 for the entire engine instead of 8.