The Miami Dolphins helped the Colts carve anotch in their record book yesterday, sending Baltimore to its second straight National Football League shutout, 42-0.

It was the first time in the Colts 29-year history (including four seasons in the All America Conference), that a Baltimore team has suffered back-to-back blanking. Only four other Baltimore teams have gone down to defeat by shutout twice or more in one season.

The loss was the club's most lopsided since Nov. 11, 1973, when the Dolphins ripped the Colts, 44-0.

Baltimore's scoring, attack remained on the sideline with quarterback Bert Jones in street clothes recovering from a preseason shoulder separation and both starting offensive tackles out for the season with injuries.

Despite a change at quarterback - from Mike Kirkland to five-year bacup veteran Bill Troup, the Colts failed to generate any offense against Miami.

Baltimore, coming off a shutout by Dallas, 38-0, in its opener last Monday night, needed four possessions before crossing midfield.

By the time the Colts managed that, Miami had a 14-0 lead, thanks in part to Troup.

On first and 10 from the Colt 45, four plays into the matchup of AFC East rivals, Troup attempted to hit wide receiver Glenn Doughty on the right sideline. Dolphin corner back Norris Thomas stepped in front of Doughty at the Miami 47 and the second-year pro took his interception down the sideline untouched for a touchdown.

Thomas' score was the first Miami touchdown by interception since 1973 when Dick Anderson returned two against the Pittsburgh Steelers.

A 20-yard punt return by Jimmy Cefalo set the Dolphin offense up at the Colt 47 with 5:51 left in the first quarter. Ten plays and three first downs later Miami had its second score, when quarterback Don Strock found Nat Moore over the middle on a five-yard pass.

Baltimore's scoreless quarter streak reached six while Miami was extended extending its lead to 28-0 by half time. Strock, playing in place of the injured Bob Griese, guided the Dolphins on scoring drives of 80 and 85 yards.

The third score was set up by a nifty 57-yard screen pass, Strock to Leroy Harris. The 220-pound fullback scampered down the right sideline, cut across at the Colt 30 and was knocked out of bounds at the two by Doug Nettles. Strock then flipped a touchdown pass to Bill Hardy.