Those people who are unlucky enough to own a DSM built around April/May of 92 often have no idea what parts to order for their cars, as DSMs changed from 6bolt to 7bolt flywheels at that time, along with many other changes. What is worse is that often even after giving a parts counter guy the exact build date of your car and ordering parts, you'll find out they don't fit. This is the fastest way to tell a 6bolt and 7bolt motor apart. This is also handy if you just bought a car or are digging in a junkyard, and don't know if the engine has ever been replaced. Checking the head bolts may not work for you, as someone may have replaced the head in the past.

	Top is an early 6bolt oilpan, bottom is a late 7bolt oilpan. There are 2 key differences between them: Note that the early oilpan flange is flat in the middle where circled (right under the crank sprocket). The late oilpan drops down in that area. Note the early oilpan side bumps out towards you in the circled area, the late pan bumps in.
	Here's a better view of the late oilpan and the flange where it drops down under the crank sprocket.
	Here's where you can check it with the car on the ground. Just slide your hand between the oilpan and frame in the circled area, run your hand up to the oilpan flange under the crank sprocket, and see if the oilpan bumps out towards the driver's side or in towards the passenger side. Out = early, in = late block.

Thanks to Mike at RRE for the oilpan flange info. As we were discussing it, I noticed the differences in the side of the oilpan, which is easier to check, as you don't even have to see it to check it.