I did my BFT at Linton in 1979/80. ISTR that the low level nevex's (500' MSD solo and 250' MSD dual) were planned at 240 kts in the JP3 and 300 kts in the JP5.
There was a slight margin in performance to catch up time, 250-260 kts was about flat out in a 3 and 330kts was possible in a 5. With full tip tanks you got a hour at LL in a 3 and 600lbs left downwind after a run in and break. In the 5 you might struggle to get to 50 minutes before fuel became an issue.....
Good training for learning to be fuel conscious! The Hawk had much longer legs and fuel (or lack of it) was rarely an issue.
These figures are from memory so may be out by a few knots but there're in the right ball park to compare them with the performance of a Hurricane or Spitfire in early WWII.
MB
PS
The Mk5A JP could mix-it
with the A10's quite well - and in 1980 the A10's considered 1000' MSD to be low level for the USAFE....they were quite easy to spot and the lead was usually being flown by a nugget with the wingman being the IP showing the lead pilot the lie of the land. (There being no two-seat A10's.)
PPS
VNE for the JP3 was 350 kts and 400 kts for the JP5.