As of the start of model-year 1972,
all Chrysler engines were blue whether they had AC or not. I've owned two unmolested 1973 340 cars; neither had air and both were blue. In '94 I looked at a Charger for sale. Next to it was basket-case '72 Charger Rallye, one of very few built with a 440 Six Pack. The engine was blue.
In the case of the 340, engine color was as follows:
- 1968 (& some very early 1969): Red
- 1969: Blue (it is not the Corporate Blue used '72-up, it's a one-off '69-only color that fades to a bluish turquoise)
- 1970-'71: Street Hemi Orange
- 1972-'73: Corporate Blue
Air conditioning did not affect the color of any Chrysler engine. In some cases, HP engines were orange while the standard variant was blue or turquoise, such as the 1970 440.
There's a lot of bad information floating around, particularly in "restoration guide" books which are notoriously wrong. Screw-type hose clamps were
only used on taxi/police packages
*, the only cars with black engine bays were either black body color or C-bodies, front suspension components and floor/trunk between the framerails were not painted, etc. Museum or not, unless you bought the car new don't assume that what you find now is how it left the factory. The Michigan State Police museum has a "restored" '69 Fury I squad car on display that's an absolute disaster. Never mind that it was originally a 383-2V car and now has a 440 Six Pack; the details are just tragic. They even refer to it as a '68 on the website, bless their hearts. Still, it's a museum piece.
And for God's sake, unless your car is a
very dark color (B9, F8, T8, Y9, X9),
paint the front of the radiator yoke black! If you want to be
truly restoration-correct, it should be done before the grille/bumper/valance is installed and sprayed upward from approximately a 45° angle--the guy at the factory that did this job was standing in a pit shooting overhead. It was by no means a precision operation; it's usually pretty sloppy and any horizontal surfaces will show body color on top. It's fairly common to find dark-color cars with the blackout, but I've never seen a factory-paint lighter or High Impact (gone by '73) color that did
not have the yoke painted. Chrysler did not want body color visible through the grille or valance opening. It drives me insane when I see a "100-point" restoration without the yoke blackout.
If you don't want to leave factory-unpainted parts like brake drums and suspension components uncoated, get yourself some Pioneer T58A spray paint and use thin, light coats. It is the closest I've ever found to a natural steel/cast iron finish. I've strove to find better but never have. I buy it by the case (6 cans).
Another fun detail: If your car originally had "Magnum 500s" ("styled road wheels" in Chrysler terminology) the brake-drum faces were painted red so it would show through the openings (the rest of the drum was unpainted). E5 Rallye Red is generally accepted as the right color, but I-H red is close enough. Want it
really correct? Apply it sloppily with a brush and install the wheels while the paint is still wet.
That's how the factory did it. Board member Stretch's '73 Charger Rallye came with those wheels (which were always 14"). There's red paint stuck to the back of the original rear wheels to this day, and the drums showed it was very obviously applied in a hurry with a brush.
The most important thing to remember is that these were not precision-crafted automotive jewels, they were mass-produced junk just like Slant Six Valiants or 318 Coronet wagons. Assembly-line guys didn't treat them any better than the cheapest Dart. They literally got the Hemi into the '68 Super Stock A-bodies by using a sledgehammer on the RH inner fender.
* Screw-type (worm gear) hose clamps were a factory-available option. In 30+ years of looking, I've never seen it on a build sheet other than police/taxi packages. Get a set of proper Corbin-clamp pliers and you'll probably prefer them to screw clamps anyhow (I do).
) start a build thread over in the "progress posts" section of the forum. I have three "active": one each for my Valiant, my Challenger, and the long-neglected Imperial. You can post updates, photos, and ask questions. If someone knows the answer, they'll let you know. Build threads are usually the most-viewed ones because we like to see that someone's working on their Mopar, even if we aren't. 
