You don't want any of the 3.0 v6 engines in the 89(first year) till they switched over to the 3.4 motor. it is a strong reliable motor, not sure but I think it was 96 when they switch to the 3.4. Check on marlin's website he has adapters listed by motor and tranny combo so it should list production years. My wife's 03 runner has a 4.0 v6 and it is a super stout motor.
the 3.0 had the headgasket issues. My 89 yota had the v6, it was a dog but it did me good. it had 235K on the ticker when i sold it. It ran good, even was down a cylinder either from the headgasket or valve, but that happened jsut before i sold it. and the current owner hasnt even fixed it and it has about 2 years later i talekd to him
The 3.0 v6 (89-95) is not that bad if you fix the hg issue. The 3.4 (96-?) is alot better of an engine but my 94 with the 3.0 and over 200xxx miles still runs strong.