Oh heck I love wildly speculating and guessing
I will assume you are at the same skill level as me and already own the same number of tools as me.
We will assume your car has 0 rust and the gas tank was drained properly as well as coolant and those are mostly clean. All of your brake lines and trans lines are all rust free and fine.
Lets say you find a low mile engine at a wrecking yard that "ran when parked" I would guess $600
You probably should at least redo the gaskets top-end and make sure you have roller lifters. $600
So now you have an engine with a freshened up top end new gaskets $1200
Transaxle you would remove from the rear cradle to redo that whole assembly so you would drop that transaxle at a transmissions shop to get refreshed probably $1500
You are now at $2700 and the thing does not roll or stop
Because of the spectacular rust free environment you can rebuild the calipers yourself and get new brake lines, rotors and pads but a new MC, $600
Because of the spectacular rust free environment your bearings a are all fine and so are your CV joints.
New Poly and Ball joints all around plus engine and cradle $600 (The cheap ball joints not the good ones we are on a budget)
New Shocks and struts $350
New tires $400 (extra 100 if you dont have a mounter and balancer as I do)
New fuel pump and sender $180
Now we are up to around 5k and it rolls and stops and the engine can sit in the engine bay and now you need belts coolant spark plugs new injector and distrib. $600
$5600 and now maybe we can work on your headlights. $400 if you just need some relays and motors.
so now we are up to 6k and you have not even touched the paint or the interior.
Because of the spectacular foresight parking it your Radiator and Heater core are fine and don't have to be replaced ($400)
You have brittle interior that fabric flakes off and sticks to you when you drive it because its warm so lets do AC. Pump, Condenser, Dryer, Evap, $1600
So now we are at 8k because i know you had to replace that heater core and radiator.
You are lucky its a hard top your interior is probably much better off than if it was a moon roof.
We buy a nice carpet cover for the dash 100
we buy some MR mikes seat covers 600
We pull the carpet that is not worn just dirty and power wash it at the local $5 diy car wash
We toss in some new speakers and use the factory radio 200
Headliner fabric and spray 95
we are at 9k it drives, its not miserable to sit in has faded paint
Some sanding pads and rattle can $500 paint looks better
Oh i forgot dew wipes they suck and 84 doors are different in ways I dont recall ... ill call those 200 and move on
now ill just round up to 10k because most of this is based on data and parts information that is more than 6 months old and we have had lots of inflation.

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