The '86 engine was setup more towards
real-world driving and not so much for the best qtr mile times. But, qtr mile times and max HP are what sell sports cars.
The '86 had the E6 high swirl heads. Much better at idle and low rpms than the E7s. The '86 had flat top pistons - dished pistons present problems with smog and detonation. The '86 had a 58mm TB vs the 60mm for 87+. The smaller TB meant better/faster throttle response. The '86 had a unique upper intake that was setup more for low-end and mid-range.
In *100% stock form*, the '86 had a faster 0-60 time than the 87+ Stangs. Again, better for
real world driving.
One of the few things you can do to an '86 without hurting the low-end HP is to get a bigger exhaust and better X/h-pipe. Even headers push the HP/torque range up.
But, 5.0's have plenty of low-end grunt anyway. So, IMHO, mod away if you want.
I decided that the Explorer intake, 65mm TB, FRPP/
BBK headers (basically the same), Banssi (sp?) x-pipe, and exhaust where good mods that didn't kill too much of my low-end.
IMHO,
GET RID OF THOSE WORTHLESS POS '86 10" BRAKES ASAP!!!. The '86 GT is a DEATH-TRAP waiting to happen with those POS 10" brakes that are sized for a 2500 lb car with 100hp! At least upgrade to the 11" 87-93 brakes that are only semi-POS. Best is to go with an sn95 set-up. But, with rims, etc, that starts getting into much more money. Still,
is YOUR life worth the ~$1000 for an sn95 setup?