The Tornado F3 could make 800kts IAS at low level prior to limitations being introduced! Possibly the fastest, however not a "real fighter".
BV, For your interest the F4 could compete for many years against many newer fighters.
In the early F4 days I saw 790kts in a F4M at low level. 750kts was the limit with wing tanks but luckily they stayed on. A typical JP error when being over enthusiastic!
In later years in RAF service the engines were detuned and thrust decreased by up to 15%!!
At Seymour Johnson in 1984 they had the Block 48 upgraded F4s to ARN-101 standards, the ASN-63 inertial navigation system, the ASQ-91 weapons release computer, and the ASN-46A analog navigation computer set were deleted. The ASG-26 lead computing optical gunsight was improved and made easier to use, with weapons control switches and displays made easier to read. Basically as a "bomb truck" a 2 seat F16 with far better range and load capability.