According to Fieroguru, The 5 spd shifter can be used, un-modified, except for a reverse lock-out that needs to be added. He said you'll get a better up-shift from 2nd to 3rd with the 5 spd when used for the F40. He modified a 4 spd for his first F40 swap but prefers the 5 spd. Just repeating what he advised.
But thanks for the info. I may end up using the 4 spd shifter if I can't find a 5 spd.
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67 GT-40 Mark II, 3800 S/C auto, 85 Fiero based (ASPP) kit. Held suspension and coil-overs all around with 2" dropped spindles. Mike's leather interior. And a whole lot more...