1.7 vs a 1.8 for a big bore kit Options

[porkchopexpress]

Looking for some advice, opinions, guidance.

The background: I currently have a 1972 with a 1.7L engine.
Recently had help from a few guys here from the world (IMG:style_emoticons/default/aktion035.gif) and found a few issues:
Rust in cylinder 3. (IMG:style_emoticons/default/barf.gif) Honed out the cylinder to get movement.
Converted the dual Weber 40 carbs to L-Jet FI
Car starts but won't hold an idle. You can keep it above 2000 rpm and it will run; made an obligatory trip around the block just to say we did!
While adjusting the valves, my buddy noticed they appears to be in excellent shape (possibly indicating engine work done by previous owner), which along with the bad idle we are guessing may point to a carb cam.

The options:
I found a 1.8L nearby that I can pick up for a deal. Was running at the time it was pulled, but that was years ago. Been sitting in a dry AZ garage ever since. Car was running with the L-jet FI, so I doubt I need to worry about the cam, but of course you never know till you look.

Thinking of picking up the 1.8 and a big bore kit from another world member here in town.

Curious if anyone has thoughts on using the 1.7 or the 1.8 for the big bore kit. I believe the 1.7 would require machine work to accept the big bore kit. Is it worth it? I keep hearing people talk about preferring the 1.7 over the 1.8.


Conditions:
I am looking at using this for a fun weekend driver and I am on a budget. I know there are lots of guys on here that can do some really serious amazing work, but its just not in the budget for me right now. Not saying its not worth it (as was debated earlier today), just not in my budget for this project.

What do you think?