I have a low milage 61 short box with 170 slant six. The engine is fine.
I also have a 61 Lancer with 170 slant six. Both are three speeds. The Lancer has a spun rod bearing.

Plan is to take engine out of my pickup and put into Lancer and sell it. Then just keep bad engine for overhaul for pickup.

Question:,.. Are the 170s twin to the other? I would not let engine go if it is numbered as this pickup is nice and I don't want to lesson the value of it by losing original engine.

That is to say, IF,.... they are traceable to the vehicle. Gordo

Both are 61s and both are manual 3 speed transmissions (?)
If so, there will be no ID number difference that will impact originallity and the swap will work.
You will have to change oil pans and the mating oil pick-up tube.
DD

Thank You, sounds good, Will changeover pan, pickup tube. Gordo