AND there are a pile of "SD friendly" camshafts available that will let you retain your SD setup such as the Crower 15511 (probably the most "preferred" SD camshaft). The general rule of thumb is that anything with a 114 Lobe C/L will work quite well in an SD application.

To flycut the pistons (to accomodate the larger valves on the new heads you want) you can get an Isky tool and use an old head to grind reliefs in the 86 flat-tops. This, in conjunction with some clay and a mic will allow you to get the clearance you need if you intend on running something other than the stock cam with your new heads.

To convert to MAF, there are literally 4 wires that need to be run, and an ECM swap to an A9L. That, and there are a few pins that need to be switched around. You don't need a new harness.

Are you certain this 86 for 3.5k is mint?? All stangs are pretty desireable nowadays, I would be surprised to see one at that price if it is in such good shape.

Good points. If you stick with the stock cam you won't need to worry about fly-cutting you pistons with E7 heads (preferably ported by Thumper) as long as you don't get some with GT-40 valves in them, or if you would rather go with an aluminum head the twisted wedge heads fit just fine with flat tops. Some people say you can't put E7 heads on the 86 or the valves will hit, but in my experience piston to valve clearance has been fine on about 90% of the conversions I've seen. If you want a little more clearance to be safe you could get a set of cometic head gaskets.