Like people said, get cheap oil and do at least TWO oil changes.
1) Put engine back together, fill with cheap oil. Then, drain and replace filter.
2) Use cheap oil and filter, start car. Make sure your repairs are correct and the engine runs fine. Let engine get warm.
3) Drain oil, and throw away filter.
4) You should be convinced that your orig repairs are fine at this point. So, use your regular oil and filter.
As people said, that little amount of antifreeze didn't hurt the lifters. If you have the money, put in new *FRPP* lifters. At ~20 years old, those lifters do *not* have much life left. And, as you see, in addition to the cost of the lifters, it's ~$50-$100 extra (intake gaskets, oil, antifreeze, etc), and a lot of work to replace the lifters.
But, do NOT get the cheap cr*p they sell at the parts stores. Get FORD - FRPP. Mustangs Unlimited, Summitt, etc all carry the lifters.
FOUR EYES RULE!
http://www.veryuseful.com/mustang/tech/misc/Mustang1986_with_Mach1_springs/
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Joe