Against the mig17 if you've got some on your tail and cant shake them off then just go vertical. Provided you have roughly the same energy (i.e speed and altitude) the mig will always stall before the mirage. Then just get out of the climb and try manovering on their six. The mig will at this point try to make it a turning fight so dont let them. If you notice that you'll not be able to make the turn just level of, gain some speed and go vertical again. The mirage has a higher service ceiling too (althouh not by mutch) you'll get him eventually.
Now there are some things to remember. Check your six to see where the migs are shooting, they tend to shoot at you while climbing and they just might get luck. Another risk is from sams as you wont have mutch speed to work with as you approach stall. Check your fuel too as you'll be doing all this on afterburner