Transmission or rear gear

I could use some help. Car is a gtpp with upgraded half shafts, driveshaft, and twin disk putting down 700 with Whipple. I will upgrade to e85 or ms109 in the spring/summer hopefully push 800ish.

The other day I pushed the car through 5th and into 6th, 155ish. 6th fell flat on its face and didn't accelerate much more so I let off. I assume it is bad to lug 6th under boost?

So I have 3.73 rear. Should I regear or wait and upgrade to the TR6060 with different ratio?

I would like to do 1/2 and 1 mile events, but also be able to go down the 1/4.

What do y'all think?

Yea the 6th gear is very tall.
Maybe change the rear end to 3.31?

Change the rear to 3.31. Wait until the tranny breaks before replacing it. Might hold a while.

jasonstang said:

Yea the 6th gear is very tall.
Maybe change the rear end to 3.31?

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wildcatgoal said:

Change the rear to 3.31. Wait until the tranny breaks before replacing it. Might hold a while.

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I have read, hopefully wrong, that I would loose my torsen in a 3.31 swap?

UUUUMMMM... I don't know if that's for sure. I am not sure if you can get a 3.31 TORSEN from someone. Not sure. But if you go get a 3.31 from a wrecked car or something... yep, no Torsen. I get beat daily by non-torsen 3.31 cars at drag strips (I suck at it, but still... I don't feel like a Torsen is needed there, but I'm not the expert on 1/4 mi diffs).

wildcatgoal said:

Change the rear to 3.31. Wait until the tranny breaks before replacing it. Might hold a while.

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Supposedly the tr6060 will do 200ish in 5th with 3.73. I am under the assumption I will break my transmission sooner or later. So if I go 3.31 now will I have to switch back to 3.73 when I do go to a tr6060?

TR6060 is SOOO much nicer. What ratios were you looking at?

Stuntman said:

TR6060 is SOOO much nicer. What ratios were you looking at?

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I'm not sure still in the early planning stage. Was going to wait until I broke mine or motor, but just found out how low my top speed was. lol

I was just told that it was capable of 200 in 5th.

jhatley7 said:

I have read, hopefully wrong, that I would loose my torsen in a 3.31 swap?

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If you're just changing ring & pinion gearing, then no, you don't loose the Torsen. The 3.31:1 gearing will bolt up to it no issue. But if you're swapping the entire carrier assembly, you'd loose it. Ford only builds the Torsen with the 3.73:1 gears, unless you find one that someone already swapped.

I'm in the same boat as you as well. I got my tune for my Whipple for 93 octane already but am putting in a full fuel system currently. In the spring I hope to be knocking on 800rwhp and don't see the MT82 lasting long at that level.

I would also like to do the TR6060 swap sometime in the spring/summer and the 3.73 gears are perfect for it so for me at least I'll be sticking with my gears and saving my pennies until the TR6060 fairy comes.

Well, spoke to Ben this morning and ordered his stage 1 TR6060! Now i have to ship of my clutch and drive shaft.

So i'll have a lightly used mt-82 and Mgw shifter up for sale next week. lol

jhatley7 said:

Well, spoke to Ben this morning and ordered his stage 1 TR6060! Now i have to ship of my clutch and drive shaft.

So i'll have a lightly used mt-82 and Mgw shifter up for sale next week. lol

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What did it cost you for the tr6060? How much else will you need to buy for it? I'm looking for a grand total basically. Feel free to PM me.

tsloms said:

What did it cost you for the tr6060? How much else will you need to buy for it? I'm looking for a grand total basically. Feel free to PM me.

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Pm'd:cheers:

drive shaft needs to be shortened and re flanged
clutch needs re-hub
Need Dakota Digital or Abbott box for speedometer.

Also Lund needs to do an update for cruise control to work properly.

jhatley7 said:

I have read, hopefully wrong, that I would loose my torsen in a 3.31 swap?

Click to expand...

The ring & pinion have almost nothing to do with the differential.

I say "almost" because you at least have to find a ring & pinion set for the carrier you have.

TexasRebel said:

The ring & pinion have almost nothing to do with the differential.

I say "almost" because you at least have to find a ring & pinion set for the carrier you have.

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But in this case, he's talking about 3.31 gears, so its already a given that it interchanges. As stated above, the ring gear can be swapped from one diff case to the next, so whether you set up the gears with a Torsen or with a clutch plate diff, it really makes no difference. The process is the same. He can keep the Torsen if changing just the gears. Its only the 3.15:1 gearing that won't work with the Torsen, and there may even be a solution to that sooner or later...