Standard & Poor's Corp. is changing its rating on the senior long-term indebtedness of Chrysler Corp. to "BBB minus" from "BBB".

Similar changes are made in the ratings on the long-term debt of the whollyowned subsidiary, Chrysler Financial Corp., with its senior long-term indebtedness changed to "BBB minus" from "BBB" and subordinated longterm debt to "BBB minus' from "BB."

"The integrity of the finance subsidiary's short-term debt remains strong, and we are maintaining an A-2 rating on its commercial paper," S&P said.

Chrysler said it was "disappointed" at S&Ps action in lowering its bond ratings, but said it was "gratified" that the rating was maintained on the commercial paper of Chrysler Financial Corp., its finance subsidiary.

(A company spokesman said he did not believe the action by the rating agency would jeopardize a comtemplated preferred stock offering that the company may put to shareholders for approval at this year's annual meeting as a way to raise money to meet Chrysler's large financing needs.

The rating company noted that Chrysler Corp. "faces record-breaking expenditures in the next few years against the background of disappointing earnings in 1977, including a sizable loss in the fourt quarter, and the prospect of another loss in the first quarter of 1978."