Go into your aircraft.cfg file and look for an fx_afterburner file. (It may be called something else like fx_flame or something, you should be able to figure it out.) Once you've found it (usually in the lights section) cancel it out by putting // in front of the entire light entry like this. //light.8 = 8, -13.00, -2.00, -0.9, fx_ALPHA_F101_AB This will turn that particular entry off and then you can try your F-2 and make sure the afterburner doesn't work (that way you know you are working the correct entry). Once you've successfully located it you can swap it out with any AB effect from any plane in your aircraft library (freeware or payware). Simply find one you like better and substitute that fx_XXXXXXX file for the one in your F-2. You may have to tweak the location of the flame by adjusting the numbers in red (light.8 = 8, -13.00, -2.00, -0.9, fx_ALPHA_F101_AB) to get it just where you want it. First number is the fore/aft location, second is the left/right and last is up/down. This entry for the VooDoo is -2.00 as it has two engines and they are not on center. Your F-2 should have 0.00 in the middle spot.
Have fun! This is the first tweaking I did with .cfg files and it doesn't take long to get the hang of it! (I do this a lot. Pretty much any plane I get with an afterburning J57 gets the Milviz F-100 AB effect linked to it!)
P.S. If the AB flame doesn't work automatically by throttle position you can usually fix that too but it's a little more involved. Let me know if you need help with that and I'll walk you through it!