T56 to flathead Ford! Anyone ever do it??

I don't think you needed to cherry pick the ratios in the PDF to make a point.

The GM V8 T5 ratios compared to the M29 T56 is apples to apples, or as much as it can get.

 

I disagree with Mickey on only needing a 3-spd. All transmissions are compromises - the more gears you have, the fewer compromises you make. The RPM drop between shifts on a 3-spd as you go from 3-something to 1:1 is horrendous. The way to keep any engine happy is to keep it in an optimal RPM range. That's why supercars who have narrow power bands have 6+ gears, high-performance motorcycles have 6+ gears, and why modern muscle cars have 6+ gears.

Many high-revving engines have a narrow power-band. The flathead does not & that's where the logic behind Mickey's (and many who think that way) comes from. There is plenty of torque from just off idle to the max RPM of 4500-5000 to pull a 3-spd and accept the RPM drop between shifts. However, ask anyone who has driven a 3-spd flathead and a 4-spd flathead and they'll tell you it's night and day. Then ask anyone who's driven a 5-spd flathead and they'll tell you it completely transforms the engine.

I don't understand the "you'll just shift more" mentality. I never will. But that's OK - there's room in this hobby for everyone.

I do tend to agree, however, that a 6-spd for a flathead will be tough to take advantage of. Many of the guys running T5 struggle to use 5th gear if they've swapped to a rear lower than 3.50:1 - especially in heavier cars. It would seem you'd need a rear gear on the order of 4.88:1 or lower to take advantage of the 6-spd...which seems like a significant added cost unless you've already got one. Otherwise, I think you'd be money ahead with an easier adaptation to sell the T56 and get a T5.

I'm not saying not to do it, but as has been pointed out, do all the math and ratio calculations you can to figure out what you really need as far as tire size and rear ratios because the T56 is substantially larger than a T5, heavier, and more expensive to adapt - all cons in my opinion for the pros of: bragging rights & an extra gear you'll rarely use. But who knows, maybe you're building a cross-country highway cruiser.

Best of luck and keep us all informed if you go down this route.

 

And who is doing that?

Grannysmith and honeycrisps are both apples, like T5s and T56s are both transmissions, but they are still different. But Haven't I already alluded to that?

Yes that's precisely what I've been asserting, that with a setup like this, every time you shift, you're in the "sweet" spot of the powerband.

We have driven 3, 4, and 5 speed flatheads. And we are in agreement that the more gears you have, the more drivable and enjoyable it becomes (to a certain point, we're not talking about adapting an Eaton 18 speed or something…..)

I don't understand that mentality either, if you're bothered by shifting, get an automatic to do it for you. Personally, we like our cars to have that 3rd pedal, you know, the man pedal.

I disagree that a 6speed would be tough to take advantage of. The car we are proposing to use a T56 in is just a project in the planning stages at this point, so we are going to have to buy things like gears anyways so that is a moot point. We got these T56s for dirt cheap so we are inclined to use them for that reason as well.

Plenty of calculations done here, which is why I shared that PDF I created, to illustrate the fact that if you use a T56 with the proper ring and pinion gears, you have just as much, if not MORE torque multiplication than if you were using a T5.





Bottom line is the numbers speak for themselves, which again is why I shared my calculations contained in that PDF. It's pretty hard to argue with math and say "oh this will never work" when the numbers are staring you in the face blatantly contradicting all the naysaying.

 

Between a bunch of us pretending the only T56s are the less ideal .50 sixth units and you throwing out only one set of ratios from each, a lot of people are.

Instead of your V6 T5 compared to V8 T56 ratios thing you have going, allow me to play devil's advocate for a bit and throw down with my apples to apples comparison:

At the power levels you're talking, the nearly identically ratio'd GM V8 T5
-weighs less
-costs less to rebuild (or acquire for that matter; your cost instance isn't relevant to most folks)
-shifts better (having to do with the 4th fore/aft gate added to the shift pattern of the same-depth offset lever section of the upper shift rail assembly)
-isn't subject to the current parts shortages from Tremec, who are either trying to sway people into buying the TR6060 nee T56 Magnum or genuinely using mfg. capacity to make parts for the newer units. (read: good luck getting parts for that one-year only box.)

There's a lot of options with clutches. But yours lacks a long enough input shaft to work without an extended pilot bearings at a minimum if you're looking into the adapter plate / push clutch option. What is the pilot section of the flathead crank? I'm familiar with the little Chevy one plus the outer torque converter one. How does a flathead compare?

Yeah, in theory, you can simply change tire size or gear ratio to make up for it. Did you ever say what tire you're considering? How long a driveline are you going to have? I like my simple 1-piece driveshafts that run up to higher speeds happily. But, if I were to go one more ratio higher numerically, I'd have more issues. But hey, if you're starting from scratch on the driveline, cool and enjoy it.

That's gear-specific and the T5 you selected has more in first gear. The comparable ratio T5 is about the same in 1-1 or 5-6 comparisons.

(yeah, I tried to ignore your S10 ratio T5 as much as possible. but it's a good thread and I'm looking forward to your completed project.)

 

If you want a six speed get a New Camaro or similar.

A Hot Rod with a Flathead doesn`t need that shit...

Your 3-speed to automatic comparission sucks
You just don`t get it about using old parts

I would suggest you use a LS1 instead of the Flathead

 

I don't think the more gears is better mentality is the best way. I agree that the addition of more gears to choose from has made driveability easier (3-4 speeds), but today the additional gears are used for fuel economy reasons, and not necessarily performance reasons.

I have a 284 ci flatmotor that is making around 196 hp at 4800 rpm. It's backed with a T5 that has the following ratios:

1st 2.95
2nd 1.94
3rd 1.34
4th 1.00
5th 0.63

With that combination, you can rip through 1-4 and have all the fun you want, without ever feeling the powerband dropping. When you want to travel at high speeds for long - throw it in 5th. The T56 ratios you listed in the PDF are very similar to my T5. I would not sacrifice the weight and size savings of a T5 behind a flathead. You could sell those trans, and pay for a nice T5 to get built.

 

If building from scratch, that's all cool. But the rear ratios you're talking about are largely aftermarket, whereas anything from 3:00-4.10 are reasonably easily found in a junkyard - where many of the backyard builders are scrounging from. So, if buying all new, then yes, you're no money out selecting exactly the ratio you need - and it's the best way forward.

You selected the worst T5 gearset to compare to though.

I didn't say it wouldn't work, I basically said it's a lot of work for very little gain. The T56 is big, bulky, and heavy. Others more familiar with them have pointed out input shaft issues you'll face - all of them able to be overcome, but extra work/expense.

You seem to have a chip on your shoulder about this. May I suggest you just do this and prove us all wrong.

I'm reminded of my favorite 'Stripes' quote:

Aaaarrmy training, sir!

...wait, that's not the one:

Lighten up, Francis.

 

Yeah I realize that there are multiple variants of the T5, was just wanting to use one that was relevant to the experience we have with the one in our '32, and, just for a quick and dirty comparison without taking into account every variant of T5 ever produced.

Never actually weighed them, but what I've gathered is that a T5 weighs ~87 LBS and T56 ~125 LBS so that's really not that big of a difference

T5 costs less, and probably costs less to rebuild as well, but either will still be cheaper than an automatic rebuild.

I think it's interesting that you say a V8 T5 shifts better, as I have not noticed that from my own personal experience driving 5 and 6 speeds, I'd say they both shift well.

There are places on the net where you can get parts for the T56, but it will invariably be slightly more difficult due to the fact that the T5 was used in tons of applications whereas the T56 was obviously not.

Honestly don't know about the flathead pilot off the top of my head… Have to look into that one. We're definitely not afraid of custom making parts where necessary, No. 1 son is pretty good with a mill and a lathe.

Probably 31" tires. Driveline, who knows at this point, but definitely a 1 piece DS setup.

Yeah the T5 we have in the '32 has too much in 1st gear, but that's probably b/c it's not a V8 T5

No.

I didn't make any said comparison between the two………………………………………………………

Old parts like that Ranger box???????????? LOL

This T5 is definitely a better gear spread than the one we ended up putting in our '32, but hey, the damn thing was free.

Admittedly this is probably true. Was just wanting to 1.) not spend an eternity compiling and comparing ALL of the T5s out there, and 2.) use the T5 we have in our '32 for a "point of reference", if you will.

Not at all! Just a little friendly banter!

 

I wouldn't use a Ranger Box.
Maybe you.......

 

Hey Chase!
You still have those two T56s?