opinions on my '65

If you are just going to sell the car. I would put as little into the car as possible. There is a lot of work that goes into a V8 swap besides just having the V8 to put in the car. While you wont need to swap the k-frame on the first gen cuda to put the 8 in . you will need a new/used centerlink for a V8 . You will also need a different transmission if you have an automatic car or a different bellhousing if it is a stick. A V8 radiator would also be a good idea. You will also need a V8 engine harness or at least modify the /6 harness to fit the 8.The accelerator pedal is also different from 6 to 8 as i recall the 6 had a rod type linkage and the 8 uses a cable.Then there is the exhaust system that you will need . All this and you still haven't fixed the front end problem.

So...... with that said I vote for the 225 .

Now are you sure the 170 is bad ? I know you said that it was ticking but that could be a cracked exhaust manifold or the lifters could need adjusting .