Why not using the canards with the smaller Mirage III and put a single J79 into it. That’s what you call a Kfir then.

That’s what I said in the opening post. But is the lightweight fighter the only answer to the question?

I see a tendency towards huge aircraft in this group. Though history showed 8at least in the 60ies) that that is the wrong approach.

There’s been a number of lightweight recommendations. Mirage 4000 wasn’t huge, at least not by century fighter standards. I don’t think the air wars of the 60s showed that small size was everything. After all the Phantom’s extra range allowed it to do things other fighters simply couldn’t. The 60’s showed fighters have to be designed for maneuverability first. Successful fighters big and small were built with this in mind.

Speaking of a 1960’s F-15, how about an earlier Mirage 4000 minus fly-by-wire and with two J-79s?

Schorsch
The closest engine in 1960 to the J-79 was the AL-7, however it was far more powerful and slightly heavier and already offered a slightly better TWR but also had a slightly worst SFC, by the time the F-4E was flying in 1968 the Russians already had the R-29 and the AL-21 which were far more powerful and had better TWR and SFC than the J-79

When was the AL-21 available? I thought it powered the Tu-28 since the early 60s.

The problem with the MiG is its very poor range. No variant ever had enough of it. A belly intake also means debris getting sucked in. Which means it needs well maintained runways and that limits it to being an excellent point interceptor with limited multirole capability.

Something bigger would be nice. How about the Su-11 with MiG-23 intakes, double delta wings and canards?