I guess it will depend on how often its driven.
I have an 86 HMMWV.
I've owned it for 20 years.
Repowered it with a 6.5 N/A about 5-6 years ago.
But it's not a daily driver so at the rate I'm going it's going to outlive me.
Got a 98 Ram pickup I bought brand new. I have put about 60 k on it in...