[64speed]

Ok it doesn't look like Legend is ever gonna come around and I don't want to hack up my tunnel for a tremec or anything like that so that leaves me with a Muncie. Everyone has called the M23Z a band aid transmission so what would you run? What will handle my expected power level? I'm not worried too much about highway RPM cause I will only infrequently see interstate use maybe two or three times a year. I will go on power tour with it but that's the only extended trip I see in the future. What trans would you run and with what gear. Rearend is a 9 inch. Tires are 235/45/18

[tom s]

I super case muncie with a 3.08 in the back and a 3.00ish first gear.Tom

[goa484]

Not everyone is calling the m23z a bandaid... Call Autogear as they will give you some other options too that may better fit your needs if the m23z ratios dont fit your needs.. They have multiple ratios available to pair with your engine and rear.

[ponyakr]

https://www.midwestmuncie.com/produc...ear-end-gears/

[64speed]

Originally Posted by ponyakr

https://www.midwestmuncie.com/produc...ear-end-gears/

Do you think my RPMs at 70 miles an hour would be livable with this trans and 3.25 gears? Looks like a good setup

[ponyakr]

There are lots of rpm calculators online, if you know your tire diameter.

https://www.google.com/search?q=rpm+...hrome&ie=UTF-8

[goa484]

You will be turning 2900 rpm. You do realize that is the earlier version of the M23z, right? Same ratios, just the M23 has a few upgrades. Either way, both are good.

[ponyakr]

Originally Posted by goa484

...You do realize that is the earlier version of the M23z, right? Same ratios, just the M23 has a few upgrades. Either way, both are good.

https://www.midwestmuncie.com/produc...y-m23-4-speed/

[The Champ]

The M23Z will handle the power. It will perform very well with 2.75's - 3.00's. 2.75's will give you an 8.195 effective 1st gear and 3.00's will give you an effective 8.94 1st gear.

With your short skinny tires (26.3" tall), I would run the 2.75's. Cruising at 2460 RPM's at 70 on the Power Tour will be fine and you still have an effective 1st gear ratio over 8.00.

If you choose to go with 3.25's and those tires - you will have lots of trouble getting traction because of the 9.685 effective 1st gear and the power that you have under the hood.

[HWYSTR455]

TKO-600 has a 2.87 first gear and is like $500 less expensive than a M23z. In most cases, it fits in place of a Muncie. It would be more compatible with a readily available 3.25 rear gear too.

The 3.00 gear sets are like $75 more than the 3.25s, last time I checked, and have seen them back ordered often.

.

[tom s]

He does not want to cut his floor!Tom

[PDC]

FWIW, I'm running the M-23 with a 3.08 and I do not believe it is a 'band-aid' behind a large displacement, long stroke motor like the 455 or the 4-1/4" stroker crank combos. I absolutely agree that a high winding small block may wheeze a little with the wider steps between gears as it drops just below its narrower power band, but even a mildly built 455 puts out enough torque everywhere on the tach to literally devour the gear spreads.

Think about your TH-400: 1st to 2nd is a full revolution step from 2.48 to 1.48. Then 2nd to 3rd steps from 1.48 down to 1:1.
Your M23 gives you the same 1 revolution step from 1st to 2nd, then .58 step to 3rd and the familiar .46 to 1 dropping into fourth - much like the 2/3 shift in the TH400.

As easily as my car will lose traction anywhere in 2nd gear with throttle only, I'm sure she would be fine with a 2.7x ring gear out back.

[HWYSTR455]

Originally Posted by tom s

He does not want to cut his floor!Tom

Yeah, I get that, but should consider it since it's not a very large 'cut' or job.

Hurst Driveline Conversions makes a tunnel patch kit to do the conversion, and it's not noticeable with a console, only barely noticeable without a console. Can be done easily with hand tools.

.

[Formulajones]

You have to keep in mind that when I say it's a bandaid, it's in reference to those that don't use an overdrive option. This trans sort of falls in the middle.

In otherwords, you can gain some highway drivability with an M23, IF you don't go crazy on the rear gear....but it's still not as good as an overdrive setup.

Like others have mentioned, there really isn't anything wrong with the M23 deal, as long as you run a 2.75-ish gear and take advantage of what that transmission is trying to do for you.

My only gripe is that I feel it's priced too high when you compare them to the 5 speeds on the market, and the M23 isn't doing anything more than what we accomplished with M-20's and ST-10's, other than the fact that it's built a bit stronger.

What I don't understand is that you've stripped the car, sent it off to AMD or someplace like that for all new metal work etc...there is nothing left stock on this thing, and you're worried about a floor tunnel?? We aren't talking about a 1-of-1 6 figure car here. Build it the way you need to do it and enjoy the heck out of it.

[Formulajones]

The short tire is killing you with the 1:1 trans.

The answer to your question is going to be determined with what you feel is a comfortable extended cruise RPM and at what MPH you want to be going. Everyone is different when it comes to this and small changes make a big difference.

If you want 70 mph cruising, 3.25's are going to have you right at 3,000 rpm with that 26.3 inch tire. You can count on any tire rolling out a bit shorter than what is advertised. Weight of the car and tire inflation affect it.

I've daily driven cars like this for decades without a problem and doesn't bother me. Others want to loaf along at 2,000 rpm. My father bought his GTO new (still has it), with 3.23's and 26" tires. He drove it for decades at 70 mph and put over 250,000 miles on the car :shrug: The engine was never rebuilt and still ran pretty darn good up to the point he wanted something bigger.

I've never done power tour but I have the feeling that large groups of them aren't going to putt down the highway at 65-70 mph.
If you're going to keep the 1:1 trans and short tire, I'd want to look at a 2.75 gear myself, as long as the trans has a steep first gear. Then you could do 70 mph in the 2500 rpm range with room to spare if you wanted to push the speed up a bit to keep up with the pack.

[JLMounce]

Formulajones brings up a good point on cost. Depending on what gear you already have in the car, if you start adding that to the cost of the swap, an m23z isn't that far off from an overdrive transmission.

I priced it for myself on my 69 bird and was fairly shocked at the price. By the time I got all the necessary parts to turn the car into a manual, added the m23z and then the price of new rear gears as well, I was near 4500 total in parts, without shipping.

I currently have a quote sitting in my e-mail box from Silver Sport for a TKO600 shipped for $5052.00. For me anyway, I'd have to save a minimum of $1000.00 to even think about doing the 4 speed over just going to the overdrive transmission.

Your car will be worth more with modern parts in it then a straight restoration, should you ever want or need to sell. At least in the current climate, the only cars that are bringing more as factory stock restorations are those cars that are historically significant collector cars. I'd hack the tunnel in a heart beat.

[torqhead]

I second what FormulaJones and JLMounce said. When I went to put my car together it couldn't be all original due to a cracked block, rescued out of the junkyard that way. You're in the same situation, so not sure about the concern in modifying the floor.

There are a number of basic upgrades to make the car reliable and tune with today's fuels and at the same time keep up with or blow the doors off a good percentage of cars on the roads today. Hell, even here in Colorado the normal traffic roads that allow you to run 50 people are running 60-70 a lot of the time.

Overdrive gives you the best of both worlds because even if you want to have a car that's a light to light hell raiser or a cruiser on the highway at higher speeds without working the motor you can have it! All the time, research and money that you're putting into this car I would recommend it.

Jason, is it time for your overdrive yet?

[JLMounce]

Originally Posted by torqhead

Jason, is it time for your overdrive yet?

It was time a couple years ago! Let me tell you how much I love cruising at 4000 to go anywhere that isn't in town!

But then I went and spent a couple grand on suspension goodies that could have gone towards the OD transmission. Oops.

[64speed]

Ok so supposing I cut my tunnel I guess the TKO 600 is the smallest so how much do I have to cut and will it work with a bench seat?

[JLMounce]

You might check with Silver Sport. They engineer a number of kits that at least with the TKO, minimal or no cutting is necessary. The TKO isn't an incredibly long transmission, I would assume you'd be fine with the bench. Linked below is a site with dimensions comparing the TKO to a Muncie.

http://www.5speedtransmissions.com/dimensions.html

As you can see, while the TKO is itself longer, the shifter locations are nearly identical. So if there's an issue with the bench and a TKO, you're probably going to run in to the same issue with a Muncie and then you decide if you want to stay with an automatic transmission, or go to bucket seats instead.