ormer senator Eugene McCarthy, 66, and Harold Stassen, 75, who was Minnesota governor 40 years ago, are on Tuesday's Minnesota primary ballot.

Also there is former governor Rudy Perpich, 54, an unendorsed gubernatorial comeback candidate. And there is Mark Dayton, 35, an endorsed Senate candidate who has spent almost $4.4 million of his own money, setting a new record for political spending in Minnesota.

Such political novelties in the election have resulted in campaignsmarked by nostalgia and sharp contrasts in style, personalities and qualifications. The convention-endorsement system for both major parties, officially known as the Independent-Republican and the Democratic Farmer Labor Party, has been strained.

Perpich bypassed the DFL convention to mount a primary challenge against Attorney General Warren Spannaus, 51, the party-endorsed candidate for governor. Spannaus is a close political ally of former vice president Walter F. Mondale, who has been in the state campaigning for him.

Perpich, who worked for Control Data Corp. in Vienna, Austria, for the last three years after being defeated by Republican Gov. Al Quie, is a colorful, folksy campaigner. His strength lies in the economically ravaged iron range in northeastern Minnesota.

The money and personality contrast is sharp in the DFL Senate primary for the seat held by Republican David F. Durenberger, who has token opposition in the GOP primary.

Dayton, heir to a retail organization fortune and brother-in-law of West Virginia's Democratic governor, John D. Rockefeller IV, has sought during his expensive two-year campaign to make it a referendum on Reaganomics.

McCarthy, who voluntarily left the Senate 12 years ago and has spent only about $20,000 in his effort to return, tried to make the contest a referendum on his past glories. He says the main issue is "seasoned judgment" in Washington in contrast to Dayton's absence of time in elective office.

On the Republican side, the party endorsement system has been tested since Quie, the incumbent governor, decided early this year to quit his campaign for a second term. Quie gave his blessing to Lt. Gov. Lou Wangberg, 41, who won the convention endorsement with right-wing support amid party dissension.

Bypassing the endorsement process were perennial candidate Stassen and Wheelock Whitney, 56, a retired investment banker and former mayor of a wealthy Minneapolis suburb who lost as the endorsed GOP Senate candidate against McCarthy in 1964.