Do you know the static compression ratio? The early 340's had 10.5:1. Probably closer to 10.0:1, but would require the best crappy gas out there (93 octane). Not sure what you have for gasoline brands, but out here in the Southwest, Chevron has the best additives.
If you know the particulars of...
Here's a link of a member just replacing his entire ignition switch.
https://www.forebodiesonly.com/forum/threads/replace-ignition-switch.41142/page-2#
Some previous owner had a huge key chain with half a pound of keys on it and has worn it out! Live with it or swap out the ignition switch. Not to sound callous, but really that's your choices.
The original truck lock shield was metal from the factory.
@pschlosser is probably right about the factory interior panels being polypropylene. Nothing seems to melt them (like glues or plastic welders) very well!
If you think about, fifty years or more later, it's not new anymore. Even if not installed, it could be brittle, seized, rusty inside, etc. So stick with a usable used part or an aftermarket part. The used one was recently working and the repo is newer!
@MOPARMITCH is right, using just an rpm gauge temporarily under the hood, you can time a Mopar by ear. Like my Dad taught me decades ago, "twist more timing into her (Before Top Dead Center) until she screams and then back her off a little!"
5° Before isn't enough. That's what plugging the distributor into the intake manifold is telling you. Try 12° before and plug the distributor back into the ported vacuum source. How does that run?
Obviously the car was modified with the 440 Six Pack and Shakerhood, but those make it stand out more if it still has those parts. A VIN would help track it down if you care to post it.
You can make your own spring for the lower radiator hose out of bailing wire if your hose doesn't have one. Just wrap the wire tight around a soda or beer can and then install into the lower hose. You have to drain the coolant, but it sure beats a collapsed hose.
I've been to Ennis, Virginia City, Whitehall, Bozman and West Yellowstone while visiting Yellowstone. Montana was the first place I was at where you could get a "traveler" (adult beverage to go)!
In the desert, if you leave your car out even one night, the damn pack rats will crawl up in there and build a nest on top of the battery using the pad. So I don't have or want one.
That said, Year One makes a good repro with the right clips. Classic Industries looks good too!
My wife loved cruising in Kitten (70 Challenger) until I bought her a 2014 Chrysler 300 5.7 Hemi. Now it's just me and sometimes the son. And he doesn't care how fast I drive or get close to another car or make tire squeaking turns! 😁
At this day and age (50+ years after they left the factory) I'm not paying more for a NOS part! Best bet is a nice "used" part. Or a functional cheapo reproduction. And yes, there are a lot of scammers out there. They are headed to a special hot place and I'm not talking the desert!
Big block or small block? But it really doesn't matter. There are lots of aluminum radiators out there now. Just get one with the upper and lower hoses on opposite corners and think 2 row over 4 row. I'd try to find and spend the extra money on one that looks like the original factory type...