I found an adapter kit that allows you to bolt a T-56 six speed in place of a toploader. Would this same adapter work for my np435? I figured that you guys would know what would fit my FE.

 

If the np435 is the granny gear 4 speed I think it is, then , yes the kit will work in your case as long as the input shaft will reach into the pilot bushing.

 

I like this idea. Who makes the adapter?

Anybody else have thougtson how this would or would not work?

I have a 6 speed one of my other cars and I love it.

 

5speedtransmissions.com sells the kit. They also sell Viper T-56 trannys for 2200 bucks, the adapter plate is $350, and a custom pilot bearing for $65, a speedometer conversion kit for $300. I think that with the gear ratios and the torque rating of the Viper T-56 it would be well worth it.

 

I can think of better things to do with $3000 than just adding 2 more gears to row in a vehicle.

 

hmmm then your not thinking of the fun of extra gears enough...

 

What fun? I've been drivin trucks with twice the gears the 6 speed has and it ain't fun. The 6 speeds I've seen are just 4 speeds with 2 od gears, not what you'd call performance transmissions. I'll stick to my 34 year old Toploader.

 

Id rather have a Toploader myself also
But a 6 speed could be fun also if they are geared right.

 

There are six gears in my "Performance car" .

 

look the tranny I'm talking about is from a Dodge Viper. I call that a performance vehicle. And besides, by my calculations, if I run 4.11 gears and 26 inch tires, with a sixth gear ratio of .5, I would be turning approximately 1900 RPM at 75 MPH. I might be able to pull some half decent gas mileage out of my truck.

 

I hear ya.

My daily driver, laid down 305 RWHP, 326 RWT, ran a 13.85 qtr mile at 105 MPH with an absolute first time driver (Me) and it get's 30 MPG on the highway. 6 speeds has a benefit and can still provide performance.

 

When you shift into an overdrive gear, it takes more torque ( power ) to do the same work than it does in direct ( 1:1) So to go faster in those overdive gears, it takes far more power than it does in direct, It's like detuning your motor to do the same thing at the same speed. Don't expect to get better mileage in OD either. They ARE good for cutting down on wear and tear on your motor by reducing the rpms. Conversely, swapping in a lower ratio rear ( higher numerically) and compensating with OD, results in increased wear on your drive line and gears in the rear. U-joints won't last as long. The 6 speed in the Viper may be in a "performance car" but that doesn't mean it's a performance transmission. That Viper's top speed in 4th will be much higher than it will be in 6th if 5th and 6th are OD. I swapped gear ratios in the rear on my V8 Ranger from 3.08 to 3.73's and my fuel mileage actually went up.

 

Fine. take your 4 speed at 1:1 and run at whatever high rpm is deemed necessary by your high rear gear ratio to get the performance out of your vehicle and you can comtemplate your mileage as my 6 speed get's 30 mpg :-)

there is no replacement for displacement.

there are no substitutes for more gears.

Very few of the great 60s muscle cars could run with my car. Not in a straight line and certainly not in the corners. Do you think any of them dreamed of 30 MPG on the highway. NO! what's the difference...6 gears.

My car is actually fastest in 5th gear, probably somewhere near 1:1. Does that mean it doesn't run in 6th. NO, it runs quite well at 80 MPH at 1800 RPM.

My car has another advantage of great aerodynamics. But, provided good aerodynamics and a powerful motor (as in torque at a lower RPM), 1:1 is just a number that people are used to. It is by no means optimal.

I think anybody that wants performance and good mileage can benefit from more gears. There is small weight penalty, and a larger price penalty. But the benefits are undeniable.

 

The 67 Fastback Stang I had back in the 80's would get 20+ MPG out on the highway with a side oiler 427 and 2-4 bbl carbs ( this is at 70-80 mph too). And it would do it with a 4 speed Toploader and 2.50 rear gears. And it still would run 13 sec 1/4's. And I'll bet if I still had the car, it would do anything yours would, striaght line, corners, whatever.(Sometimes it's no the car you have to worry about, it's the driver) You don't have to have OD to get performance and mileage. The fact still remains that it takes more power to turn an OD gear than it does with a 1:1 ratio. A direct drive trans will also out last an OD trans too because of the simple fact that theres less stress on the transmission from the OD gears. How much did you pay for your 6 speed car? I'll bet it was a pretty penny, and I can buy a lot of gas with the difference in what you paid and what I've spent. If paying thru the nose for a 30mpg performance car or $3000 for a "performance" 6 speed transmission is what turns you on, then go for it. But it there's always more economical alternatives.

 

Ok, I'm gonna step in here
You said your car runs better than a 60 model muscle car... DUH!
Technology has come a long way in that length of time. The extra 2 gears you have isn't everything.
Sure, it's part of the technology But also its better bas, better fuel systems, better ignition systems, etc
Also as you stated Aerodynamics... which they have learned a lot about since the 60s
So I wouldnt say your car is better just because it has 2 more gears
Because that's not completely true