Wow...great car, wonderful price, and wonderful inspiration!!!!
I agreed with a lot of the commentary, but, not all of it. I loved the guy who talked about Walmart battery. Guess what? I put a walmart 700 CCA battery in mine two years ago, and its still going strong and turns over the engine just great. At $89 it came with a two year replacement warranty plus 60 month pro-rated, while the $134 700 CCA battery sold at Advance Auto came with a 1 year warranty and 24 month prorated !! Some purists are just ...well..in my opinion ...a little anal.
In my case i bought a "PROJECT" 74 Challenger with 904 auto for $5,000. The owner had started a restoration. He found and bought a performance shop built 360 off of craigslist, (it came with the invoice of $3900 and parts list from the performance shop. Talked with the shop and they figured at least 400 crank HP... Not a beast but a great street engine. ). He also had the interior seats reupholstered with Legendary Interiors new all white seat covers and foams. He also put in, a full new exhaust 2 1/2" with Flowmaster 40 (original) mufflers, and a set of patriot headers. Then he lost his job, and wife made him sell... so i found in my belief a real bargain. He figured he had about $11-12K out of his pocket. I got it for $5K. His loss my gain.
I put into the car about $7,000 worth of parts for new Walmart battery (lol), new Champion 26" aluminum radiator, new front windshield and Used rear window (professionally installed), new engine mounts from Mancini racing to hold that engine, new exterior door handles and new interior door and window handles, new window fuzzies, door weatherstripping, window weatherstripping, New front bumper, used console, $1400 for vintage air system (factory air long gone sold old factory box for $250). New gas tank, and sending unit. New dash cap, better set of good driver quality door panels, New carpeting, and new headliner. A cheap am/fm stereo with CD and aux inputs, plus speakers... couldn't see paying for good stereo as, the car has in it the flowmaster 40's so kinda loud to be listening to much music. New 235x60x14 tires as my wife liked the mag wheels it came with where were 14", for spare tire went to salvage yard and picked up a like new 15" donut that fits, along with a scissors jack and handle... they fit in a nice leather bag i picked up. Lots of miscellaneous other parts...like, bought a new design fuse box and wired it in to the harness to replace that 43 year old rusted fuse box. New radiator and power steering belts, and new heater hoses... new voltage regulator...etc. New brake pads, and front hoses..
Then I put about 500 hours of my labor into restoring it and installing everything !!... put whatever value on that that you may... I figure about $20 hr patching the rust on rear quarter panels, and around rear window it was rust free from doors forward. I also then overhauled the 904 with new torque converter (2500 stall), and new seals and clutches. Then stripped down the entire body (chemical paint remover), and put on the Epoxy primer, and 2k primers, and blocked it twice. I figure that if i had to pay a restoration shop for all of this the, car would quickly cost more than it is worth. so 500 x $20 =$10,000. Oh I also "grafted" from a 2002 Jeep Grand Cherokee the power seat track...so i now have a power seat... that was a lot of work !!
Lastly, I paid $2500 to a professional painter to do the Final blocking, shooting of Plum crazy urethane and clear paint). It came out great...
So, adding it all up
$5K for car/engine +$7k parts + $2.5 K to painter = $14,500 total money investment plus 500 hours $10,000 of my labor i've got about $25,000 invested in her.
Still could use a new rear bumper (their hard to find for a 74, and 70-73 will fit, but only if you buy the matching bumper support brackets). Also, it needs some kind of striping on it...haven't decided yet what to put on. Also still needed is to swap out the rear differential. Right now it has the original factory 2.73 open diff, that does nothing for the built 360 (it has in it a Mopar Performance 508 292 duration cam). I bought a used 3.23 suregrip, and debating whether to change the ring/pinion to 3.55 before installing. I also bought (its in the $7k parts) a used A518 overdrive auto... but, its a lot of work to put in, and i should rebuild it before putting it in. If I do would probably change the rear diff ring/pinion to about a 3.71... so holding up on both while i think about it. Also, haven't installed the rocker panel trim, and don't have wheel well trim.
At this point, i think the car is worth in the $25-35K range... It isn't for sale anyways as i'm now enjoying it... Now if someone offered me $52K i could reluctantly change my mind, but doubt it that will happen..