This is info I got from the 1994 MBI published Charger, Road Runner, Super Bee restoration guide by Paul Heard.
I am just typing what is found in this book:
In chapter 3, Power plants, it is broken down year by year from 1968-1971.
It reads basically what BLK 68 R/T has said,
all big blocks installed in Chargers in 1968 were painted turquoise, except the 426 Hemi.
It goes on to list the short blocks for the Charger 383 engines, 2bbl and 4bbl, and stated NO 383 MAGNUMS were installed in the Charger cars.
It reads: unique identification plate, sometimes called pie tins, used on Charger for 1968, were: 383 4BBl, and 440 Magnum, both in red.
1969:
It says all 383's the pan, dipstick handle and block, should wear the same finish as in 1968 EXCEPT the 383/335HP version.
The 335HP engine and the HP 440 should be painted Hemi orange, Ditzler EQE-60626 with 25% Ditzler DX-265 flattening agent, to correctly darken it.
It goes on to claim SOME 383/335HP V8 were painted turquoise when equipped with air conditioning.
But ALL 440/375HP V8 engines, even those equipped with air conditioning were painted Hemi orange, using same formula as the 383/335HP Magnum/Road Runner engine.
And once again states the 383 Magnum was not available in the Charger, and the Charger' special identification plates(pie tins) remained unchanged from 1968
1970:
The 383 V8 engine 2BBL and 4BBl both had drop in compression ration, but no change in HP rating.
The 383 Magnum was still not available in the Dodge Charger.
All 383's in the Dodge Charger should be painted Chrysler Blue, and all 383's in Super Bee and Road Runners should be painted Hemi Orange, again except for a FEW with air conditioning.
All early 383 V8's had forged steel crankshaft, but later 383 2bbls with automatic trans had cast crankshafts installed.
1970 engine ID plates were done in orange, not red.
1971
383 2bbl remained an option on base Charger, and should be painted Chrysler Blue, and all 383 4bbls should be painted Hemi Orange, using same shade as previous years.
It is very unlikely any 383 4bbls were painted blue, even with air conditioning, because there was no other 383 4bbl as in previous years.
In the past workers might mistake a high performance power plant with air conditioning as one of the low powered engines and painted it turquoise
383 4bbl V8 was still the standard engine for Super Bee and Road Runner, but this engine was now optional on all Charger models, except the Charger R/T.
The special engine ID plates(pie tins) were shifted in 1971, 383 4bbl was deleted, and replaced with 383 Magnum. The P/N for the tins were same as in 1970 and the 340 4bbl tin was introduced. 1971 engine ID plates were done in orange, not red.