Over time, parts like the A/C compressor will start to wear internally and even if the refrigerant pressure is still good, you will notice poor performance from your A/C system.
You also have to consider the evaporator and condenser as well. As the condenser ages, the fins will start to decay and will show signs of build-up (white powder). These things are common on any older car, but relatively inexpensive to fix for you, because you have Fox Mustang.
I recently replaced the evaporator on my 93' and the A/C won't freeze me to the seat, but it does keep me cool on hot days. Had I put down a few more bucks for a condenser, I might be a bit cooler still on these hot summer days.
On the HP issue, 2300's can make tons of power if you apply the right parts to them. At a minimum, you can advance the timing on your 88' and gain a few more HP.
One last thing, you might want to change the A/C pressure switch out for a new one as it could also be the source of the problem.
89' Mustang convertible, high compression N/A 2.3.
85' SVO under s l o w deconstruction.
93' hatch currently under development
Last edited by ohc230; 07-03-2018 at 01:46 PM.