Also the first generation 22r's are different than the 22re including the heads so the exhaust will be different than your 22re.
There were 2 versions of the 22R/re the early tall deck and the later short deck. The short deck has a slightly lower block than the tall deck. The short deck uses 2 less links in the timing chain. There are also differences in the head that make the head from a long deck incompatible with the short deck and the same goes with the other. Now a 20r Hilux head is compatible with an early 22r which is actually an upgrade in power when you combine the 22r block with a 20r head. An 81 comes with a 22r so if you have a 20r it has been replaced. As mentioned above just behind the oil check stick there will be a flat spot clean it off and it will tell you what you have.
