the 2nd diagram i posted (using single corrector), being a "theory" to me at the time, then seeing what 66coupe posted confirms it to be the correct way to do it.

im converting back to auto tommorow, and am running 3.7's and a speedo corrector. Ive wired it up as mentioned, so will see how it goes !!

..double post

yep shift points are fine, and speedo is correct !!!

Just to note:: by using One speedo corrector and using the method fordfairmont illustrated above, you save yourself $50 for the 2nd corrector and install time, But
you do lose Cruise Control.. The dash microcomputer must do something to the signal for CC and by cutting the dash output, CC will not work at all.

I found this method still the best, save money and time, speed is correct, my speed limit is now 150 but chip will fix this, and I never used to use CC anyway, so no loss there.

just a heads up.. take it easy.