Quote Originally Posted by Poil336 View Post
i bet it would be ok. you'll replace the top end, so the only thing you'll have to worry about are pistons (which are bulletproof if you tune it right) and rod/main bearings. 139k isn't that high
Pistons, and rings which have been worn in under certain conditions and exceeding / changing them may drastically accelerate wear.

Personally I wouldn't do it. However, I believe there have been many here that have top swapped high mileage engines successfully.

Also keep your transmission in the back of your head during this.