Read what I posted. The 87-88 T-Birds use the SN95 arms which are longer than the Fox arms. Below is take from this post https://forums.corral.net/forums/showthread.php?t=781854
All fox arms are the same length 79-93
SN95 arms are 1.33" longer than fox
T-Bird arms are the same length as SN95 arms.
79-86 have control arm mounting positions 1/2" per side further inboard than 87-93. 1" total narrower track width than 87-93.
mix and match (all compared to 87-93 stock track width)
79-86 stock K-member + fox arms = 0.5" per side, 1" total narrower track width
79-86 stock k-member + SN95 or T-Bird arms = 0.83" per side, 1.66" wider track
87-93 stock k-member + SN95 or T-Bird arms = 1.33" per side, 2.66" wider track
79-86 Schneider modified k-member (additional 0.5" beyond the 0.5" already build into the narrow 79-86 k-member) + SN95 or T-Bird arms = 0.33" per side, 0.66" wider track as compared to stock 87-93.
94-95 SN05 spindle adds 0.118" (3mm) of track width per side when replacing a fox spindle.
96+ SN95 spindle adds 0.315" (8mm) of track width per side when replacing a fox spindle.
I can tell that on my 83 T-Bird I installed both the Griggs Fox control arms and the Griggs SN95 control arms and the Fox units were definitely shorter than the SN95 units. I ended up using the Fox arms to keep the wider tires under the fenders. I also have the Griggs front K-menber, Griggs coil overs, and '96+ SN95 spindles on the T-Bird with Cobra front brakes. I was battling all kinds of clearance issues and this was the combination that worked best in my application.