T56 to flathead Ford! Anyone ever do it??

T56 to flathead Ford! Who has do it??

Who out there has mated a T56 (6 speed) to a Ford Flathead V8? Just picked up a couple T56s and this might be the thing for the next flathead powered project?

Yeah, we did the required HAMB search and found plenty T56 and T5 accounts but didn't seem to find anything using one with the flathead.

The T5 plugged into a flathead is such a great combo. We run a non WC T5 with a flathead in our roadster and it's great. We have a 36 Ford with the stock 3 speed box and it's "limited" when compared to the T5. So why not a T56? More is better, right? One more gear, better gear spacing, etc, etc.

So who has done it??

 

Subscribing! I'd like to know this answer too. Got a flatty and plan on putting it in a Model A coupe, was going to do the T-5 route, so if I could do a T-56 why not.

 

We tried and never got to use 6th gear, it was too high for rear end gearset we had and the flat didn't have enough power to pull it

 

The flatty will not make enough torque to make the 6th gear useful without a super low rear gear.

Otherwise, use a LS1 T56 (or a LT1 T56 with a LS1 input shaft swapped in) and the MeLeod (or similar) plate adapter. This makes the front of a T56 "look" just like a T5, a V8 T5, that is. You would certainly need an extended custom pilot bushing, and would have to make sure that the splines are in the clutch hub fully.

 

Thanks for the helpful info guys. Anyone else have thoughts on this???

 

what are your plans with the engine and carbs?

 

What rear gear did you have? What is the O.D. ratio of 6th in a T-56?

 

Just like T5's it depends on which T-56 you have.
http://en.wikipedia.org/wiki/T56

It looks like most of them are .50 or .62 to one though. That would turn a 4.11 to a 2.055 in the engine's way of thinking and take some torque in most cases.

 

I run one behind a 1989 305 (roller everything, mild cam, small carb), with a 0.50:1 top gear, in a car with a 2400lb curb weight. I run a 31" tall rear tire. So far, I have found that the best rear gear is a 6.00:1, in my 9". Sounds crazy, but you have to remember, with the 0.50:1 overdrive, that is like a 3.00:1 with a old-school 3 or 4 speed. With the tall tire, it "seems" like an even taller gear.

With a flatty, even if it is hopped-up, it is going to take some fancy figuring to pick out a rear ratio (vs. tire size, and factoring in vehicle weight) to make sure that all 6 gears are usable. Otherwise you basically have a 4-speed.

 

Oh, and if you do go through with this, you will want to move the shifter to the inspection plate area. This can be done with the Keisler kit.

I did not feel like taking apart the whole deal, nor did I want to pay, so I didn't.

I found this writeup online, and did that. It worked fine:

http://www.performancetrucks.net/fo...22/t56-front-shift-conversion-install-485277/

I even lopped off he old shifter tower and welded shut the holes, for more seat clearance.

 

The proper ring and pinion ratio to match the ratios of the T56 should make all gears very useable. We have one in my son's Chevy P/U which granted isn't a flathead, but all the gears are very useable after a 4.88 gear swap. Initially it had 3.08s in the diff, and even with a mildly warmed SBC making ~400 LB/FT of torque, all that torque still couldn't overcome the 3.08 R&P gears to make 6th useable.. He has the MN6-T56, which has the deepest gears; 2.66:1 1st and .5:1 6th....

One of the two T56s we acquired recently is the MN29, the one with a 2.97:1 1st and a .62 6th..... This would be the one we use behind a flathead, as the gears aren't quite as deep, and the conservative 400 LB/FT rating is plenty for such an application.

We run 4.11s in our '32 Highboy with a "mystery"-T5, which we believe to have a .72:1 5th gear, and 31" tires.... At 65 MPH it turns roughly 2085 RPM and develops enough toruqe to mantain this speed.... If we were to build another, similar car, but use a T56 this time, then 4.88 R&P would give basically the same end result.

4.88-R&P 31"-tires 65-MPH .62:1 6th = 2132 cruising RPM.

This is not exact, but very similar to our current setup.



Thanks for sharing that link on the shifter relocation gimpy!



Found this ratio chart showing the different ratios available with the T56:

93 F-body with (M28) 6 speed Torque rating 360 lbs-ft.
1st: 3.36
2nd: 2.07
3rd: 1.35
4th: 1.00
5th: 0.80
6th: 0.62

93 F-body with (M29) 6 speed Torque rating 400 lbs-ft.
1st: 2.97
2nd: 2.07
3rd: 1.43
4th: 1.00
5th: 0.80
6th: 0.62

94+ F-body with (MN6) 6 speed Torque rating 450 lbs-ft.
1st: 2.66
2nd: 1.78
3rd: 1.30
4th: 1.00
5th: 0.74
6th: 0.50

 

The 1993 M28/9 is a one-year-only transmission. As far as I know, you cannot swap the input shaft with a later (longer) unit as the gear tooth count from the later models. I have just been "told" this, and have never had a 1993 unit across my bench, so check before you move forward. I might be wrong, but checking is better than having an oopsie moment later.

Edit: I looked it up, it appears that the M28/9 has an input shaft with 29-teeth. After that, they go to 31-teeth. It appears that there are other internal changes too.

 

Honestly, a 6-speed behind a flathead seems like a waste. If you choose rear end gears to match the trans (either way, high or low), you either really don't need 1st gear or you don't need 6th gear. If the flatty is making ALOT of torque and power, it might be a different story.



Malcolm

 

I think if I see Keisler re-brand someone elses design one more time, I'll vomit.

These ratios are really a nice setup. I can't speak for the flathead needs though.

29 and 31 input tooth counts are both still used, all through the TR6060. But the 93 F-bodies were the only narrow gear 29 tooth input with single cone synchro; everything else 29 is double.

I'll say this is pretty true. Even a torque engine does fine with the 2.95 first / .63 fifth V8 T5. Going from a perfectly good one of those to a T56 can be a waste in a lot of cases. BTDT.

 

I have been running a T56 in my 1994 Impala SS for many years. Great tranny's. I run 4.10 rear gears which makes the engine turn about 2,000 rpm at 75 miles per hour. 6th gear is only useful on the highway.

I have never driven a flat head, but I would tend to think the double over drive of the T56 would be too tall with the relatively low torque.


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This is correct. The M28 and M29s had a 29 tooth 1st gear that measures approximately 1.050" and the MN6 has 31 teeth on 1st and measures approximately 1.135" Measured in terms of gear height.

Then wouldn't a 5 speed be a waste as well? We can start off in 2nd gear with the T5 in our roadster, it really is too short in that particular T5, we believe the 1st gear to be 4.03:1 in this particular box.

We can also start off in 2nd in our T56 P/U by slipping the clutch just a tad. Does this mean that 1st gear in the T56 is useless? Absolutely not, it just doesn't last long.. but the T5 in our roadster, you're shifting into 2nd before you even clear an intersection.

As said, all the torque in the world couldn't overcome the 3.08 ring and pinion gears we originally had with our T56 P/U, and that is my point here, that the ratios of whatever tranny you run, or whatever ring and pinion you run, really don't mean much by themselves. The way we see it, is that it is a balancing act between the ratios of your gearbox, and the ratio of your R&P. (obviously tire diameter factors in as well) You want gear ratios that are complimentary to each other: giving excellent torque multiplication, but still hopefully having the ability to act like "highway" gears for the gas-mileage when cruising in OD. And the idea here is to gear the rear axle in such a way that ALL gears are useable, regardless of whether or not you're using an old school flathead, or, some kind of modern ground-pounding LS engine.





So far we have one guy who has actually run a T56 behind a flathead, and we don't know his ring and pinion gears, but my guess is that his R&P gears were not ideal for the deep ratios of the T56. T56s have deep gears, so it makes sense that to have ALL SIX gears useable, you must use a R&P ratio that compliments the deep ratios of the T56 (something between 4.11-5.13, or even more, depending on tire size).

Our T56 P/U was useless in 6th gear BEFORE the re-gear to 4.88s. Now it hauls all the way through 4th, and you have TWO "gas-mileage" gears for cruising. 5th is great for cruising between 45-60 MPH and 6th is great for 60+ MPH.... It turns just a tad under 2000RPM in 6th @ 70MPH....

We have no intention of removing the T5 in our '32... Just toying with the idea of a T56 for one of our next projects....

 

We have a T-5 behind our really mild 8BA, it is PERFECT with a 3.00:0 gear and 29" tires. The six speed would be a waste of time, just not what a flathead powerband can utilize.

 

Guess we'll just have to try one behind a flathead and see for ourselves since everyone who is saying it is a "waste" has apparently never actually tried a T56 behind a flathead.


The quintessential essence of hot rodding is using what you have available. And we certainly have a T56 available.

Torque multiplication FTMFW.

 

I applaud your efforts and logic. I am looking forward to positive results! I love my T56.

 

Not saying a bad idea but not worth it. What is the lowest HP motor that was placed in front of a T56? I don't think you want to try to match that HP output in a Flathead motor, because that is what you will need to make the T56 work behind it.

The flatie has borderline grunt to make the T-5 work, just not enough for the T56.

 

Unfortunately Casey isn't with us anymore, but he DID have a T56 behind his flathead. I just now remembered this.

A quick search turned up a couple threads where he commented about his flathead/T56 setup:


Last post in this thread:
http://www.jalopyjournal.com/forum/showthread.php?t=266131&highlight=flathead+t56

Post #7 in this thread:
http://www.jalopyjournal.com/forum/showthread.php?t=195572&highlight=flathead+t56

Post #2 in this thread:
http://www.jalopyjournal.com/forum/showthread.php?t=264102&highlight=flathead+t56



Malcolm

 

HOW TO HOOK IT ALL UP??

Thanks guys, for all the comments.
For those who have done it and those who have figured it out, which bell housing and clutch system do you use to mate a T56 to a flathead?

I'm assuming its something like the T5 route where we used the 2 piece bellhousing and stock pressure plate and flywheel but swapped in a clutch disc from an Astro van that splines up with the T5. Any thoughts on this ??

 

Well, this will make the front look like a V8 T5:

http://www.thegearbox.org/catalog/item/3838217/4803441.htm

Looks like this will get you the rest of the way:

http://www.speedwaymotors.com/Offenhauser-Chevy-T-5-Transmission-to-Flathead-Adapter-Kit,35589.html

-or-

http://www.speedwaymotors.com/Speedway-Chevy-T-5-Transmission-to-Flathead-Adapter-Kit,35584.html

When used on an SBC (with an LS1 T56), an extended throwout bearing is required. Presumably this will be the case on the flatty.

If there is enough material, it might be possible to mill the required amount off of the face of the bellhousing where the transmission mounts, to make the extended pilot bearing unnecessary, and to better the spline engagement on the disc. Examination of the actual product would be necessary.

As for power concerns, my 305 produces 170 hp and 255 lb-ft of torque. Pulls just fine.

 

at long as you are at it, why not pump up the flathead with all the power and strong ignition that you can? run a quick change rear too.

 

Thanks for sharing those posts Malcom, it sounds like Casey was pretty pleased with his T56 & flathead combo.

And thankyou Gimpy, for posting up those parts

Jalopy Joker, if we do go through with this and run a flathead/T56 combo we will more than likely beef it up a at least a little. We dumped the points ignition for HEI on the '32 we got and never looked back on that one......


Put this chart together (see attachment) to compare and contrast the data for the T5 and T56 final drive ratios to actually see what the difference is.

What the chart shows is that if you properly gear the rear end to match the T56 ratios, it has:

1.) a better, more useable 1st gear that isn't as short as the 1st gear in this T5 we're using for our comparo.

2.) a tighter gear spread from 1st through 6th, which is good because every time it's shifted into the next gear, the RPM drop is not as drastic and therefore will keep the engine in the fat spot of the powerband, where it is making peak torque and power.

3.) Finally, If we have now crunched the numbers to establish the benefits of the T56 over the T5 in 1st through 5th, what about 6th gear? You know, the one that is supposedly "useless" because of the "lack of torque". Well, as my spreadsheet shows, If you were to use 4.56 gears, the final drive ratio in 6th for the T56, is very similar to the final drive ratio for the T5 in 5th with 4.11 gears.

T5 in 5th W/ 4.11s: 2.9592

T56 in 6th W/ 4.56s: 2.8272

thats a total difference in the final drive ratio of .132 …………………..

Wait for it…. Wait for it…. How about the final drive ratio for the T56 with 4.88s????

A T56 in 6th W/ 4.88s: 3.0256 Wait, What?!?!? 4.88s+T56 will actually give you a tad bit MORE torque multiplication than the 4.11s+T5 combo. If a flathead can power the T5+4.11 combo just fine, then it definitely can power the T56 4.88 combo because it has even more torque multiplication to assist the flatheads lack of torque and power.

 

A Flathead doesn`t lack of torque......

Six speed behind a Flathead.....i don`t get it.

Just build a proper engine and all you need is a three speed..... and 3.25 R&P

 

Compared to the modern overheads that alot of T5s and T56s are behind, they do...................

And apparently you're not the only one...................

Then why not just say screw the transmission all together and run a multistage clutch assembly? you don't really need any gears/transmission, but they are sure nice to have.

We have a 3 speed in our '36. To say that it sucks compared to either the T5 or T56 is an understatement at best. Non synchronized first, limited torque multiplication, limited top speed, non-constant-mesh, blah blah blah blah. Yes it works. But the modern gearboxes are better. This is not 1938, we have options, so why not utilize them?

If you wanna do something everybody and there dog has already done for decades and decades by running a 3 speed, that's fine, absolutely no problem. We prefer to embrace progress and technology, and try something creative, different.

 

Don`t get me wrong , i`m not saying "use a 32-39 box" , but 6 gears means a lot of shifting......

I run a 304 ci Flathead and a three speed in my roadster.

I go around a roundabout and 125 mph in third if i want.......
This is torque.....

Use one of the 80s Ranger 3+od boxes.....
No need to change R&P

 

I say go for it if you have it. I am running a T5 behind my flatty and love it but I am putting a T56 in my 36 Chevy and should love it even one more! I love shifting, if its too hard for you guys they do make automatic transmissions these days

 

Agreed.

LOLZ, ROFLZ!