Principles
God's laws do not change (6:34, 17:77, 18:27, 33:62, 35:43, 40:85, 48:23), and any messages that were revoked or lost to history is replaced with the final revelation (2:106).
The Qur’an is a confirmation of the truth (and only the truth) in the earlier revelations (2:41, 2:89, 2:91, 2:97, 2:101, 3:3, 3:50, 3:81, 4:47, 5:48, 6:92)
Nothing new (as far as God's laws are concerned) was said to Muhammad (41:43)
The Qur'an is sufficient as guide (6:38, 6:114, 7:52, 11:1)
The Qur'an is clear commandments (24:1, 45:18) no need to make or take assumptions or conjectures
Follow the best of speech (39:18)
Application
If something is in the Qur'an, then what is in the Torah or Bible is validated as revelation.
If something is not in the Qur'an, then what is in the Torah or Bible must be man-made additions.
If we take parts of the Torah or Bible that are not revelation as part of religion, then we have taken those writers as partners to God (9:31, i.e. mushrik)
Arguments
The prohibition against swine meat is found in the Old Testament, in Leviticus 11 (Clean and Unclean Food) detailing the reasons for swine meat being prohibited, among a host of other animals, including rabbits, reptiles, amphibians, and shellfish.
NONE of these details exist in the Qur'an, therefore the prohibitions are man-made (application 2). Consequently, we can conclude that pork was NOT prohibited for the Jews.
In Qur'an (2:173, 5:3, 6:145, 16:115) khinzir is traditionally translated as swine. I believe this is based on prior knowledge that swine meat was prohibited for Jews. In (2) above, we prove it is not.
The traditional translation introduces a linguistic error in a perfected book — the mention of a specific animal does not fit in the verse, which mentions types of things we are not to consume. Consider an analogy: when discussing modes of transport, you do not mention a specific model of car alongside modes of transport.
The only mention of swine in the Qur'an is in verse 5:60 but it's a different word - الْخَنَازِيرَ (khanazeera, not khinziri) altogether, although they have the same root. God's language in the Qur'an is exacting, and we cannot gloss over the differences in usage and form of the same root, and assume that they're all the same.
It is quite clear from the above arguments that swine may not be the best (principle 4) - or necessarily correct - translation of khinzir, especially if it was chosen due to a mistaken belief.
Are there other meanings of khinzir according to the lexicon which may fit the verse better as suggested by argument #4?
Lane's Lexicon lists a few, amongst others, maggoty, stinking i.e rotten. Let's see what happens when we apply this meaning to the translation of the verses.
Revised Translations
2:173 He has forbidden you: dead meat (carrion), blood, rotten meat...
5:3 You are forbidden to eat animals that you find already dead, blood, rotten meat, any animal over which any name other than God's has been invoked...
6:145 Say, "In all that has been revealed to me, I do not find anything forbidden to eat, except for a dead animal, flowing blood, and rotten meat - It is impure
16:115 He has only prohibited you from eating carrion, and blood, and rotten meat, and that which has been dedicated to other than God
Conclusion
In conclusion, I believe "rotten" is a better (see Principle #4) translation for khinzir in the verses due to the following reasons:
does not assume that the prohibition of pork in the bible was part of revelation, when there is no proof of such
it is a type of meat instead of a specific animal, and fits with the verses mentioning types of things you cannot consume
it doesn't raise questions about other species close to swine (boars, capybaras, tapirs, etc) or having pig in their name (guinea pig?), or various other nations and languages classifying other types of animals as pigs
it fits better with "impure" in 6:145, instead of making conjectures about why swine meat could be impure
it is more logical and doesn’t introduce questions about using pig parts in human bodies (heart valves, for example), or pork-derived condiments (gelatine) or food colourings
does not lead to extraneous man-made prohibitions such as touching pigs, or wearing pigskin
... and pork is not really prohibited by the Qur'an.
Note
It is interesting to note that the prohibitions in Leviticus 11 are mostly repeated in the hadiths – Sunni hadith (no carnivores, reptiles, or amphibians) or Shi'ite hadith (no shellfish etc).