It all comes down to how well it has been maintained. I see Rangers with with any engine make it to 250k with no problem at work. But I also see ones that need major engine work at 100k because they were neglected. Yes there are cases where they were taken care of just as they were supposed to be but had issues prematurely due to parts going bad long before they should have. On general however, if you take care of it it will take care of you. I say stick the 3.0 in it as it is the easiest and fastest swap. Then keep on top pf maintenance.

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2010 Ranger Sport 4X4, SOLD!!!
2002 F350 CCLB 7.3PS Lariat 4X4, 136k miles, 4" exhaust, BFG All-terrains