Hymn 1.165 is a dialogue. The Maruts ask Indra why he comes alone and what he holds against them. He says the hymns and libations are his, asks where they were when he had to kill the dragon alone, and insists he killed Vritra by his own strength. They grant that no god is his equal, and he declares himself pleased with their praise. In 1.170 a riddle about lost hope is followed by Agastya's plea that the Maruts are Indra's brothers and he should not kill 'us'; a reproach to Agastya for neglect; and an order to prepare altar and fire. In 1.171 Agastya tells the Maruts he fled in terror from Indra and set aside the oblations made ready for them, and asks forgiveness.
Indra, roaming the sky, meets the Maruts and they exchange praise. Agastya learns of their talk through austerity, prepares an oblation for Indra and hurries there, but praises the Maruts in three hymns and then wishes to give them Indra's oblation. Indra perceives it and protests with the 'nothing today, nothing tomorrow' verse. Agastya answers that the Maruts are his brothers, calms the agitated god, and then makes the oblation over to the Maruts. When Soma is pressed Indra makes them drinkers with him; hence Indra with the Maruts is called Marutvat.
What is different here:
The oblation was prepared for Indra and diverted to the Maruts (the reverse of RV 1.171.4 as Griffith renders it); no argument about the dragon; adds a frame and an ending in which Indra shares Soma.
Sources: Hymns of the Rigveda, tr. R. T. H. Griffith (1896), hymns read for the Vedic layer; The Brhad-devata attributed to Saunaka, ed. and tr. A. A. Macdonell (Harvard Oriental Series 6)