Glad rag,
Good pic and quite consistent with what I said. The Israelis learnt very quickly that exposed tail end jet pipes represented big IR targets. Their very practical response was to extend the jet pipes so that the relatively small warheads then in use would explode further away from the critical bits in the fuselage, blowing off just the aft end of the pipe and increasing their chances of surviving a missile hit.
Skyhawk also had a relatively long jet pipe, which helped reduce the IR signature. Jets with the engines located right at the rear (e.g. Tornado) had, in my experience, simply massive signatures, requiring fairly big (and heavy) flares to offer any real chance of protecting the aircraft.
Hope this helps
Engines