At these colors, you have to do something. To obstruct opps' bidding, to discourage p from preempting in a minor, but above all to pay tribute to this nice hand.
(Edit: was Burges') Leufken's rule (with 11 cards in the two longer suits, open at game level) comes to mind. But RHO passed so p could have a strong hand, and a 4♠ opening would work terribly if we belong in 6♥.
You chose 1♠. What? 1♠ in 2nd seat at IMPs with 8 points, among which a sec jack? Yes, why not. If p is strong with a good fit, this hand will not be a disappointment. If p is weak, a 1-level opening may bluff opps out of their minor suit slam or 3NT (or they may reach 5m and take the finesses over you). And if if p is strong with a misfit .... oh well, we are nonvulnerable and it's IMPs.
The auction proceeds (opps are silent):
1♠-2♣
2♥-3♦
3♥-4NT
5♦-7♥
pass
Plan the play. The opening lead doesn't matter. Solution in hidden text. Remember, the difference between made and down one is 1560, the difference between down one and down two is only 50.

Help

(Pass)-?