number1_kid

Hi guys.

I got alot of help on here so here comes another question

I have a 1987 GT cobra 5spds.

I have the long gay gears 2.73

I want to put 3.73 in it next week.

Went to local ford dealer ( idiots ) for a speedo plastic gear.

I told them my transmision and my gearing I want to put in it.

They still did no know what color speedo gear and size I needed.

So can anyone tell me what speedo gear I need????


Thanks
Kevin M

number1_kid

What is the correct speedo gear for 3.73 gears in a 1987 5spds GT???

Red 21 tooth?????


thanks

number1_kid

top

89gtsleeper

well what size tire are you running in the rear, because that will make a big difference also.

Black Snake

BTW no such thing at a 87 Cobra GT. Unless ur Canadian.

I use the Red speedo gear for 3.73s 21 tooth

89gtsleeper

Axle Ratio 6T 7T 8T- Drive gears

Driven gears

2.73 - 16 18

3.08 - 18 20

3.27 16 19 21

3.55 17 20 -

3.73 18 21 -

4.10 20 - -

4.30 21 - -

4.56 - - -


Note: Calculated driven gears are based on normal mustang tires (815 revs/mile) and the formula listed below.
Note: If the tire's are larger diameter than stock, go to the driven gear with (1) less tooth than calculated.

Driven Gear Teeth = (Drive gear teeth x axle ratio x tire revs/mile)/1000


Type Trans 16T 17T 18T 19T 20T 21T

Manual wine white yellow pink black red

Automatic blue green gray tan orange purple

89gtsleeper

ok, that came out crappy... just click this.
D & D performance - Speedo Gear Chart

These guys also are extremely knowledgeable, and if you call them during the week, they should have all the answers for you.
(248) 735-6220

number1_kid

tires dont really matter
only me off by a 1 mile or 2 at over 70 anwyays


I juste want the correct gear for the 3.73 gearing

I am running 225-60-15 in rear

but few weeks changing back to 225-50-15 same as front

And yes I am Canadian so I do have a 1987 Cobra GT