question on rear differential for 66 T-bird

66thunder · Post by **66thunder** » Thu Apr 05, 2012 10:18 am

What size rear differential and how many spline axles did a 1966 T-bird come with from the factory, would like to put a posi rear and 4.10 gears in my 66 T-bird

redstangbob · Post by **redstangbob** » Thu Apr 05, 2012 10:35 am

Should be a 9 3/8" with 31 spline. Do you mean 'Equa-Lock' center section? Posi is in brand X

scumdog · Post by **scumdog** » Thu Apr 05, 2012 3:29 pm

4.1 gears?

Your fuel use will go way up, your tyre wear increase (very likely!) and your top speed will be about 85mph...

66thunder · Post by **66thunder** » Fri Apr 06, 2012 10:05 am

Its just a weekend warrior car, for cruise nights and car shows, so its a 9" rear and sorry looking at 4.11 gears

bughunter · Post by **bughunter** » Fri Apr 20, 2012 12:15 am

9", 28 spline is stock, I hope to have my 3.70 trac loc installed next week.

ELTBIRD · Post by **ELTBIRD** » Mon May 23, 2022 8:41 pm

What does AXLE 01 mean on my 66 hardtop build sheet?

ELTBIRD · Post by **ELTBIRD** » Mon May 23, 2022 8:42 pm

Also .. Trans code is 4. What does that stand for?

jtschug · Post by **jtschug** » Wed May 25, 2022 12:24 pm

Page 36 of this document:

http://vintagethunderbirdclub.net/T-Bir ... evised.pdf

4 = C6 transmission

1 = 3.00:1 Open diff

390 "Z-code" vehicles had 9" 28-spline axles, 428 "Q-code" cars came with 9.375" 31-spline axles.

Vintage Thunderbird Club International

question on rear differential for 66 T-bird

question on rear differential for 66 T-bird

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Re: question on rear differential for 66 T-bird

Re: question on rear differential for 66 T-bird