How good would the F-4 be re-engined with AL-21s?

I’m looking at specs for AL-21 which powers the Su-17 and Su-24. It’s identical in size and weight as the J79, certainly smaller than the Rolls Royce Speys the RAF shoehorned in. Except AL-21 military power is as much as the J79 wet, and even has slightly lower sfc.

So in theory an F-4 operator with good relations with the Russians, say Iran could’ve made this re-engine happen? What kind of performance are we looking at?