the e303 will give you problems , go with a comp cams or crowler with a 114 lsa and your good to go. The e303 isnt that good of a cam theres much better out there that work with SD. Even the comp cams XE270HR works good with SD. Im running the nx264 and it runs great.
E cams do not run particularly well with SD without a custom tune. It's getting harder and harder to find places that are able to burn a chip for SD computers. The hardware is still out there... it's the software for Ford SD EECs that's difficult to find.
I am planning on leaving my cam and heads alone and just going with 1.7 Cobra RR, new valve springs, a Cobra intake with a 65mm TB and leaving the injectors at 19 lbs. Any thoughts?? Yes, I am still SD.
Keep the LSA around 114* (stock cam is 115* btw) and the keep the duration smallish (something around 260* advertised or so) and it will be a hit or miss with the valve lift selection. Seriously, just do what thousands of other 87' and 88' stang owners have done and convert to mass air - it opens a whole new door in the light of "what do I want to do next?" instead of "what can I do?".