1962 convertible dual-quad Chevy Impala with 409 068 X engine

My heart really isn't into selling this. My mom bought it for my dad - it's his dream car. But he's not using it much, it's taking up garage space and I've been asked 50x to post this. So here I am. But yes - I'm mailing this one in. If it gets interest in the +$75k+ range, it will go...shy of that won't win the day but in 6 - 36 months, it might. If not, I'll relist it a couple times per year until it does (and if it doesn't, my son can take it to prom). Body as you can see is clean, engine has been rebuilt (engine details below - original to the year and make but beyond that is hard to tell).
Tech lingo from the restoration folk and Jack Gibbs - foremost expert on 409s and the person who saved this block. Bored 60 over. About 500 miles since it's been rebuilt. The engine has a beautiful growl.

Your 409 has ARP fasteners for head bolts, crank mains, rod bolts, cam bolts, flywheel and clutch bolts, and harmonic balancer bolt. It also has a custom ground competition cams camshaft. It is a hydraulic roller billet cam made to perform like a stock 409/425hp cam like in 1963. The original cams were solid lifter and had to be adjusted all the time. It also has a true roller timing chain.

Power steering. I was told power brakes, but I'm not feelin' it. 2, 4 barrel carbs.

The X on it in theory means it was a special racing series block. Or it means it was made when one foundry went on strike and shipped everything to another more modern factory for completion. July 1962. I've been told the X and other stuff makes the engine worth $10k+ more than other similar blocks...but deciphering Egyptian would be easier than getting an unambiguous answer out of true Chevy enthusiasts.

https://tunedauthority.shootproof.com/gallery/4518820/- slide show - pin is 1212.

We paid $65k for this - it was supposed to 'run and look like new'. It looked great, but within 9 months of getting it, Mom & Dad put $23,000 into making all the stuff work and look good (although the body actually has always been in great shape). And that $23k was a friend doing the work at a substantial discount. Once Dad was all set to go, the $%^&! engine blew...mismatched heads I was told. So $24,000 later, everything mechanical now works like a champ too. To my knowledge, today there isn't a thing on it that doesn't work like it's supposed to. But it's 55 years old...like people, that might change tomorrow. I have all the receipts - 17 pages worth.

Granted, I don't know a lot more than a low-end car buff, but I know more insane car nut-jobs than most and thus with their help I should be able to differentiate people with real interest from scammers or people that like to do test drives in their spare time. But feel free to ask questions as I've already typed 5X more than I expected and I know I'm leaving stuff of importance out.