What is primaries "ran" on the Electoral College? If they were by popular vote?

[West_Midlander]

What if party presidential primary elections were based on a 538 elector system, 270 to win, same state distribution in the presidential primaries as in the General Election.

The party will have to legislate what will be the course of action in the event that no candidate reaches 270 electors. (Any 1 of these 4 options)
1. Plurality of electors wins
2. Plurality of vote wins
3. Majority of vote wins (with or without RCV: ie. requiring nominee to "have" a majority)
4. Revote at the convention until someone has 270

What effects would there be in presidents/presidential candidates in the present, past and future?

What if presidential primaries (and/or the General Election) were based on popular vote (plurality) or if a majority was required (ranked choice voting instead of FPTP in the event that no one has 50+% AND no EC)?

[West_Midlander]

An example.

Democratic Presidential Primaries, 1972
270 electors to win

Candidate:	Senator George McGovern	Former DNC Chair Henry Jackson	Governor George Wallace	Representative Shirley Chisholm	Former VP Hubert Humphrey	Representative Wilbur Mills	Senator Ed Muskie
Home State:	South Dakota	Washington	Alabama	New York	Minnesota	Arkansas	Maine
Delegate soft count:	237	52	80	17	98	6	48
Contests won:	24	7	6	2	6	1	5
Popular vote:	4,053,451	505,198	3,755,424	430,703	4,121,372	37,401	1,840,217
Percentage:	25.3%	3.2%	23.5%	2.7%	25.8%	0.2%	11.5%

Red = McGovern, Yellow = Jackson, Green = Wallace, Light Blue = Chisholm, Blue = Humphrey,
 Pink = Mills, Grey = Muskie

Democratic National Convention, 1972

Candidate:	1st Vote	2nd Vote	3rd Vote	4th Vote
McGovern:	237	238	239	239
Jackson:	52	52	52	—
Wallace:	80	84	84	—
Chisholm:	17	17	—	—
Humphrey:	98	98	98	—
Mills:	6	—	—	—
Muskie:	48	48	64	214
Abstentions:	0	1	1	85

The first vote: Electors vote as expected.
After the first vote: Mills withdraws his name from the Presidential ballot but offers no endorsement.
The second vote: No change except: one of Mills electors votes for McGovern, 1 abstains and four back Wallace.
After the second vote & the third vote: Chisholm drops out and throws her support behind Muskie, 16 of her 17 delegates follow suit with one choosing McGovern.
After the third vote: Jackson endorses Muskie for President. Jackson's electors are either solidly in the Muskie camp or leaning towards it. Word reaches the Humphrey camp preceding the fourth vote. Humphrey phones Jackson and confirms this; He endorses Muskie.
The fourth vote and the nominees: Wallace launches an independent campaign and encourages his electors to abstain. McGovern privately offers Muskie the Vice-Presidency. Muskie accepts. The electors of the DNC pass a motion, 453-84 (with one abstention), to choose the presidential candidate on a plurality of delegates. The Democratic ticket is McGovern-Muskie.

[West_Midlander]

Here are historical results. Since 2000, only one result flips (2008 D).

On that note, how do you think McCain v Clinton works out?