is it likely to fail due to the increase in hp and torque?

The 4:10 holds up just fine with the 6cyl but don't expect very good gas mialage.
I've heard of people mating them to 4.9 conversions and while they'll melt the pavement at launch, 16mpg is about it but there a tough lil tranny.

Its alright if you don't abuse it. There is a difference between driving hard and abuse. My buddy has a 3.4 that he drives really hard with a 3.4 and it runs like a champ.

I, however, split the case of a 4:10 with my 2.8 on the dragstrip. Guess its the luck of the draw.

i had a 4.10 with a beefy V6 and it held up real good untill i mashed 2nd real hard at about 5K once.......then it split the case all the way arround and seperated it a good 1/2"
but on the other hand i had a rebuiltunder 6K mile 4.10 mated to my SBC and it held up perfect, but im swapping it out for the 3.32 because it wasnt verry "user friendly"

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Rich AIM: ONE FAST 2M8
white-- 86se V6 daily driver
Gold--- 86se 355 SBC

quote Originally posted by paulcal: The 4:10 holds up just fine with the 6cyl but don't expect very good gas mialage.

The 4.10 has a taller 4th gear than the later 3.65. The 4.10 will run within 100 rpm of the 3.65 at highweay speed. Based my experience with both an 88GT (5 speed) and an 86SE (3.65) you lose about 4 mpg with the 3.65 on the highway and by extrapolation maybe 5 with the 4.10. In real numbers the 88GT gets about 27 MPG on the highway and the 86SE 23 MPG.

quote Originally posted by sanderson: The 4.10 has a taller 4th gear than the later 3.65. The 4.10 will run within 100 rpm of the 3.65 at highweay speed. Based my experience with both an 88GT (5 speed) and an 86SE (3.65) you lose about 4 mpg with the 3.65 on the highway and by extrapolation maybe 5 with the 4.10. In real numbers the 88GT gets about 27 MPG on the highway and the 86SE 23 MPG.

I could be wrong, but based upon information I've picked up over the years, I have been using the following individual gear ratios to determine the overall ratios for the various 4 speed trans:

Final drive: MY8 = 3.32 M17 = 3.65 M19 = 4.10

Gears: MY8 M17 M19
First: 3.53 3.31 3.53
Second: 1.95 1.95 1.95
Third: 1.24 1.24 1.24
Fourth: 0.73 0.81 0.81

Overall: MY8 M17 M19
First: 11.72 12.08 14.47
Second: 6.47 7.12 8.00
Third: 4.12 4.53 5.08
Fourth: 2.42 2.96 3.32

My math might be a little weak, but I have used the following equation to calculate the speed in the various gears:
Speed (mph) = D x RPM / (GR x FD x 336)

D = Tire Diameter
RPM = Revolutions Per Minute
GR = Specific gear ratio
FD = Final Drive ratio

Using 25.3" as the tire diameter (about the same as stock GT) my calculations yeild the following results:

At 3,000 RPM the car with the 4.10 will be traveling at 68 mph; the car with the 3.65 will be traveling at 76 mph. Of course, the equation can be solved for a specfic speed (e.g. 75 mph) to determine the anticipated RPM.

Thus, while the 4.10 does have a taller 4th gear, I don't think it will run within 100 rpm of the 3.65 at 70-75 mph. By my calculation the 4.10 would run about 350-375 higher RPM at 76 mph. However, even that difference may not be significant to some people.

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FierOmar

[This message has been edited by FierOmar (edited 04-20-2004).]

Years ago I had a 4.10 fiero.
It would launch like a mofo...

Top speed was really shitty though. I drove other 5 speed cars b4 my 4.10. I always caught myself trying to shift into a gear that wasnt there.

Again, by my calculations, the theoretical speed (without regard to wind resistence, etc) at 6,000 RPM for the same car with 25.3" diameter tires would be as follows with rhe respective trans:

MY8 -- 186 mph
M17 -- 153 mph
M19 -- 136 mph

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FierOmar

quote Originally posted by FierOmar: I could be wrong, but based upon information I've picked up over the years, I have been using the following individual gear ratios to determine the overall ratios for the various 4 speed trans: Final drive: MY8 = 3.32 M17 = 3.65 M19 = 4.10 Gears: MY8 M17 M19 First: 3.53 3.31 3.53 Second: 1.95 1.95 1.95 Third: 1.24 1.24 1.24 Fourth: 0.73 0.81 0.81 Overall: MY8 M17 M19 First: 11.72 12.08 14.47 Second: 6.47 7.12 8.00 Third: 4.12 4.53 5.08 Fourth: 2.42 2.96 3.32 My math might be a little weak, but I have used the following equation to calculate the speed in the various gears: Speed (mph) = D x RPM / (GR x FD x 336) D = Tire Diameter RPM = Revolutions Per Minute GR = Specific gear ratio FD = Final Drive ratio Using 25.3" as the tire diameter (about the same as stock GT) my calculations yeild the following results: At 3,000 RPM the car with the 4.10 will be traveling at 68 mph; the car with the 3.65 will be traveling at 76 mph. Of course, the equation can be solved for a specfic speed (e.g. 75 mph) to determine the anticipated RPM. Thus, while the 4.10 does have a taller 4th gear, I don't think it will run within 100 rpm of the 3.65 at 70-75 mph. By my calculation the 4.10 would run about 350-375 higher RPM at 76 mph. However, even that difference may not be significant to some people.

I can't argue with the math. I thought that the 0.73 4th gear came with the M19 not the 0.81.

I've owned a 4.10 and also my son has a 3.65. They seem to run close to the same rpm at highway speed. Your estimate of 68 MPH at 3000 rpm is about right. It could be the 4.10 and 3.65 both have 0.81 4 th gears. My 3.65 has 205/60/14 tries which calculate about an inch smaller than the stock 185/80/13 for an '84 with a 4.10. That plus a little tachomater discrepancy could result in experience that they run close to the same rpm on the highway.

I have a 4.10 in my 85 gt and at 3000 rpm itsrunning 66 mph so at 6000 I was going 132 mph. The civic behind me was much slower.

Ps I have been abusing mine for over a year without a problem.

[This message has been edited by Earl (edited 04-22-2004).]

quote Originally posted by sanderson: I thought that the 0.73 4th gear came with the M19 not the 0.81. .

I've seen it posted both ways. I'm running a 4.10 now and it sure feels like it's got the .81, but I don't know for sure. 4th gear in the 4:10 seems like 3rd gear with the 3:32.

Again, I have used info that I have picked up from published sources over the years, but cannot identify the source at this time. It does seem odd that the engineers would go with the 1.24 - 0.73 split with the 3.32 rear end, but use the smaller split (1.24 - 0.81) with the 4.10.

Also, if the 4.10 does, in fact, have the 0.73 4th gear, it appears that it would run about only about 100 more rpm at 70 than the 3.65 rear end with the 0.81 4th gear.

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FierOmar

The .81 does make sense for a performance transmission mated to a small motor. The RPM drop would be a lot and torque would be reduced 10%. The RPM drop from first to second is a lot too, but it is better handled in second than fourth.

Never driven the 3.32 geared car, but with a duke and that high gear...

GL