Anybody go from 3:55 rear gear to 3:08?

[CHANMADD]

I have a 600 hp, with a 2.88 Posi rear end, with a T5, and 27" diameter wheels, Its great..
2 nd gear is close to 100..

[MKS427]

I run a 3.08, same size tires (they're shorter than the 15"s, which increases gearing), TKO 600 w/.64OD and 572hp 585tq. If I could get a 2.90-2.80 rear gear (not available for the 8.8 Ford), I would and switch to the .82 OD. With the 2.87 first gear it tops out around 45mph and NT-01s aren't sticky enough to put it to the pavement. The 2.32 first gear in the Toploader seems better suited for these cars, but lacks an OD. Currently, I'm at 2000 rpm @ 75 mph in fifth. You would be about 2550 at 75 mph and 2730 at 80 mph. According to my calculator, you are 3150 at 80, currently. I know 3.00 is available for the 9", which would get you to 2660 rpm at 80 mph.
ALSO, you can change the OD gear without buying a new transmission. Contact Dederichs Motorsports for parts. He is in Fort Worth. 682 365-5555 .64 OD would get you to 2450 @ 80. Tremec has just released their TKX transmission, it is dimensionally identical to the TKO600, but is gasketed and has better syncros. Dederichs can set you up with that too and you could sell the old TKO. I believe a .73 OD is available with TKO 500 0r 600 gear sets.

[Dwight]

Coach had the same problem with his .82 Tremec. We swapped the main shaft and fifth gear. It's been a couple of years ago but I think the parts cost about $350 and we easily sold the .82 shaft for $250. He paid Eddie $200 labor to swap parts.
We pulled and installed the tranny in his Cobra.

[Dwight]

I found over the years IMHO 3.55 (3.50 for a nine inch) 26 inch rear tires and .062 5th gear tranny makes a great combination for a Street Cobra, Coupe.

Oh yea '66 Fairlane

You have enough gears for the street light and can cruise at 2,000 rpms.

Of course your cam plays a big part. Your motor small or big needs enough torque at 2,000 rpms to push your car.

[eschaider]

Originally Posted by MKS427

... If I could get a 2.90-2.80 rear gear (not available for the 8.8 Ford), I would and switch to the .82 OD. ...

My 2.73 gear is an OEM Ford gear for their 8.8 like used in T-Birds and Mk VIII's. They also have 2.92 and 3.08 available and if you go to the aftermarket I believe there are 3.00 and 2.90 ratios available. The 3.00and 2.90 are not hunting gear sets. If you select a new gear set you should look for a ratio that is a hunting ratio. It will run quieter.


Ed

[MKS427]

Originally Posted by eschaider

My 2.73 gear is an OEM Ford gear for their 8.8 like used in T-Birds and Mk VIII's. They also have 2.92 and 3.08 available and if you go to the aftermarket I believe there are 3.00 and 2.90 ratios available. The 3.00and 2.90 are not hunting gear sets. If you select a new gear set you should look for a ratio that is a hunting ratio. It will run quieter.


Ed

I have an 8.8 solid axle. Do you know of gears below 3.08 for it? I couldn't find any. I have a FFR and am considering swapping to IRS. I may have a choice between T-Bird and Mk VIII or '15 and newer Mustang. Any thoughts on the two? 3.08 and bigger is all I've found for the current platform.
Thanks,
Mark

[eschaider]

Originally Posted by MKS427

I have an 8.8 solid axle. Do you know of gears below 3.08 for it? I couldn't find any. I have a FFR and am considering swapping to IRS. I may have a choice between T-Bird and Mk VIII or '15 and newer Mustang. Any thoughts on the two? 3.08 and bigger is all I've found for the current platform.
Thanks,
Mark

My preference, Mark, is the earlier 8.8 housing out of a 2007 to 2010 Ford Explorer. It is a HD version
of the T-Bird, MK VIII or SVT Cobra housing. It also has massive dual front mounts that dwarf the Cobra
generation housing. Here are the two side by side;



The Explorer version is a bit heavier and Ford added some "Vitamin C" in some of the tender areas to
offset warranty issues in the much heavier Explorer chassis. There are a number of nice covers for the
back. Do not use a stock cover they are paper thin and break like this SVT Cobra piece,



Ford offers a reasonably priced HD cast cover for the housing that looks like this;



There are all manner of differentials available for the Ford 8.8 rear end,Tru-Trac, Quaiffe etc, but I liked
(and bought) the Wavetrac Torque Biasing unit, click here => Wavetrac for a nice visual of how
the interior geared mechanism works (there are no clutch packs). An extra added benefit to the
Wavetrac is it comes with a lifetime warranty.

The nice thing about the remaining IRS rear spindle hardware is you can purchase it all from Ford because
they make the pieces available just for kit cars. You have a choice of either the newer 2015 -2020 rear
knuckle kit or the earlier 2003/2004 Cobra style knuckles depending on which you like better. You can also
buy the parts from a salvage yard and save significant $$. Ford offers a full kit car version of their OEM rear
brake package or if you like, you can use stuff like Wilwood.

Although they (Ford) do not offer them I would opt for the Mark Williams billet steel caps,

They cost right at $100 brand new on eBay.

The mounting cage for the IRS is really simple to craft;



The "tall" gears are an over the counter item at your local Ford Dealer. If you go to Tasca's online FRPP site
you can get a little break on the pricing.

Here is an OEM Ford 2.73 ring and pinion (ring only in the picture)



You can buy these brand new right over the counter at Ford parts counter pricing or you can buy excellent
used parts off eBay below $100. This particular one was going for $80 or so — because no one wants them!
Not only that they usually come out of granny's daily driver and are in near new condition!!

Use your mouse, your keyboard, Google and a little initiative and you can probably do even better. These were
the first items that came up in my Google search. A focussed search will probably do better.


Ed

[MKS427]

Originally Posted by eschaider

My preference, Mark, is the earlier 8.8 housing out of an 2007 to 2010 Ford Explorer. It is a HD version of the T-Bird, MK VIII or SVT Cobra housing. It also has massive dual front mounts that dwarf the Cobra generation housing. Here are the two side by side;


Ed

Thank You.

[H-Rod]

Originally Posted by MKS427

I run a 3.08, same size tires (they're shorter than the 15"s, which increases gearing), TKO 600 w/.64OD and 572hp 585tq. If I could get a 2.90-2.80 rear gear (not available for the 8.8 Ford), I would and switch to the .82 OD. With the 2.87 first gear it tops out around 45mph and NT-01s aren't sticky enough to put it to the pavement. The 2.32 first gear in the Toploader seems better suited for these cars, but lacks an OD. Currently, I'm at 2000 rpm @ 75 mph in fifth. You would be about 2550 at 75 mph and 2730 at 80 mph. According to my calculator, you are 3150 at 80, currently. I know 3.00 is available for the 9", which would get you to 2660 rpm at 80 mph.
ALSO, you can change the OD gear without buying a new transmission. Contact Dederichs Motorsports for parts. He is in Fort Worth. 682 365-5555 .64 OD would get you to 2450 @ 80. Tremec has just released their TKX transmission, it is dimensionally identical to the TKO600, but is gasketed and has better syncros. Dederichs can set you up with that too and you could sell the old TKO. I believe a .73 OD is available with TKO 500 0r 600 gear sets.

Good info.
I did buy my trans from Dederich also.

I doubt I want to pull my trans due to a leaky rear that needs re-sealing anyways. BUT...the other info was great none the less.
Thanks!!!