OK so I'm doin an engine swap in my early A, going from slant 6 to 360. Well the 360 is out of a truck that had a factory manual behind it and I'm putting a 727 on it instead. Sounds ok right? Well, I ran across a section on crankshafts in "how to hotrod small block mopars" I believe and it made a mention of an incompatibility issue, specifically that a manual crank is different than an auto crank in that the pilot bushing is 1/16th of an inch larger on a manual crank. I have done some research on the issue and it appears that the torque converter needs to have a hole in the back of the crank for it to ride in so it keeps it centered and level. This is a entirely new issue ive never heard of so I'm hoping someone can enlighten me. I want to order my stall converter but am holding off until I get this issue resolved. Ive read on other forums to just pull the bushing out and it will work or to hammer it further into the crank, or that it wont make a difference at all and don't worry about it. So whats the answer? Thanks for the help
Manual to auto swap
- Thread starter bblock383
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mguner
How many is too many?
You should have no issues with the auto swap. The pilot bushing hole is of no consequence to the converter register which is present on all the cranks. Early models had different sizes but that was pre 68.
67Dart273
Well-Known Member
Here's the confusion. The hole in the crank is STEPPED
The ORIGINAL old school cranks ......depending on the engine..........
the far deep smallest part was the manual pilot. ("WAS") On auto cars sometimes this was not machined full OD OR WAS NOT deep enough
The converter rides in the LARGER hole near the rear of the crank. It is important to note that earlier engines / converters had a SMALLER converter register. (68? and earlier)
Now the confusion is that newer engines (famously Jeep) uses a pilot that sits in the CONVERTER register and does not use the original, smaller pilot hole
This is the newer manual pilot which sits in the CONVERTER bore. These can be had in both roller bearing and "bushing" types
If you USE the newer Jeep style, you won't have to worry that the old pilot is "full size"
In your case, going to an auto, NONE of this is an issue
The ORIGINAL old school cranks ......depending on the engine..........
the far deep smallest part was the manual pilot. ("WAS") On auto cars sometimes this was not machined full OD OR WAS NOT deep enough
The converter rides in the LARGER hole near the rear of the crank. It is important to note that earlier engines / converters had a SMALLER converter register. (68? and earlier)
Now the confusion is that newer engines (famously Jeep) uses a pilot that sits in the CONVERTER register and does not use the original, smaller pilot hole
This is the newer manual pilot which sits in the CONVERTER bore. These can be had in both roller bearing and "bushing" types
If you USE the newer Jeep style, you won't have to worry that the old pilot is "full size"
In your case, going to an auto, NONE of this is an issue
Ok so what the book on hotrodding small blocks is true but doesn't affect me? I wont have to pull out the bushing or anything? The transmission is an 80s 727 if that matters. So is the 360 if that matters also. Just want to be clear on this. Also, if I get a 2400-2500 stall will I be able to cruise the highway at those speeds or will the tranny burn up from the converter not locking up? Ive read different things across the internet about how a converter works in relation to RPM and some say a stall only does its thing when you mash the pedal but works normally when your just cruising. Others have said unless your past the stall RPM even at cruising it will slip so cruising the highway at 2500 would burn up my converter\tranny. How is it actually? Thanks
mguner
How many is too many?
Your 80's transmission is probably a lock up converter type anyway. The first description of the converter is correct though. At cruise slippage is marginal and not really noticed until you get into the very high stall race type converters.
I haven't been able to find a lot of info on this tranny but what I did find is its a non lockup out of a 4x4 truck. I figured it was a lock up as well considering the age but it appears I got lucky. So cruising at the stall RPM or just under wont overheat it?
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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You would most likely be cruising at under the stock convertor's stall too. And here's why;
Let's say you had a 2200TC, and your car was geared to turn 2200rpm at your cruise speed.So you motor up to that cruise speed, and back off the throttle.Until the speed is stabilized, you will back off , back off and back off until the power output of the engine matches the cruise requirement. Now look at your tach. It will not be 2200. unless your engine only puts out that cruise requirement, like 30 or 40 hp. More than likely your cruise rpm will be under 2000, or even less. That means the TC is slipping at least 10% or more. And they go 200,000 miles or more, that way.
Now getting back to your question; No, the TC will not burn up, nor any other part of the transmission, from being operated this way.
Of more importance is the fact that the 4x4 truck tranny will not fit into your car. To make it fit will require the complete tear down of the tranny to swap out mainshafts and then a car extension, and probably a car governor as well.
And there's nothing wrong with running a loc-up in a mild combo.
I hope by now you have figured out that the crank issue is a one way street,mostly. After 1966,you need the right crank to make a bolt-in swap to a 4-speed into where an automatic once was. The 4 speed can be made to fit any 66up crank; it just might not always be a bolt-in.
But any 66 up LA crank will accept any 66 up 904/727 based TC/trans.
So for you, it's a non-issue; with the 71 or later 360 and the 80's tranny.
Now, one more thing; Why do you think you need a 2500TC?
What's your combo? What gears,rear end,car weight or body,tire size,cam, and intended useage?
The stock truck TC might just be fine, depending on the answers to these questions.
I guess you also know that most A-bodies require: a specific engine-type K-member, and engine brackets, and motor mounts, and often a throttle cable, and car specific KD linkage, and a car filler tube, and car manifolds ? And 9 inch brakes, if you got 'em will have to go, and I would not run that old style M/C either.You are just asking for trouble, and then all your work,time,and money, could be lost in an instant, not to mention people's futures or lives.
Let's say you had a 2200TC, and your car was geared to turn 2200rpm at your cruise speed.So you motor up to that cruise speed, and back off the throttle.Until the speed is stabilized, you will back off , back off and back off until the power output of the engine matches the cruise requirement. Now look at your tach. It will not be 2200. unless your engine only puts out that cruise requirement, like 30 or 40 hp. More than likely your cruise rpm will be under 2000, or even less. That means the TC is slipping at least 10% or more. And they go 200,000 miles or more, that way.
Now getting back to your question; No, the TC will not burn up, nor any other part of the transmission, from being operated this way.
Of more importance is the fact that the 4x4 truck tranny will not fit into your car. To make it fit will require the complete tear down of the tranny to swap out mainshafts and then a car extension, and probably a car governor as well.
And there's nothing wrong with running a loc-up in a mild combo.
I hope by now you have figured out that the crank issue is a one way street,mostly. After 1966,you need the right crank to make a bolt-in swap to a 4-speed into where an automatic once was. The 4 speed can be made to fit any 66up crank; it just might not always be a bolt-in.
But any 66 up LA crank will accept any 66 up 904/727 based TC/trans.
So for you, it's a non-issue; with the 71 or later 360 and the 80's tranny.
Now, one more thing; Why do you think you need a 2500TC?
What's your combo? What gears,rear end,car weight or body,tire size,cam, and intended useage?
The stock truck TC might just be fine, depending on the answers to these questions.
I guess you also know that most A-bodies require: a specific engine-type K-member, and engine brackets, and motor mounts, and often a throttle cable, and car specific KD linkage, and a car filler tube, and car manifolds ? And 9 inch brakes, if you got 'em will have to go, and I would not run that old style M/C either.You are just asking for trouble, and then all your work,time,and money, could be lost in an instant, not to mention people's futures or lives.
Aj the tranny isn't anything special its just a 727. t has the long tailshaft and everything. Not a short shaft like an RV or anything. I think I have a picture of it somewhere but theres no external signs it came out of a 4x4. Looks like a car tranny to me. If someone could run the numbers on it that would be great but so far no one has been able to find much out about it. Never thought about it before but now that you brought it up I guess it cant be a 4x4 tranny. Guy I got it from said it came out of a 80s dodge pickup with a 360 and it was pulled to do a manual swap but had been recently rebuilt. I do know it probably did come from a 360 since it has the weighted converter.
67Dart273
Well-Known Member
Yes should be pretty much a bolt up but ensure the converter is weighted properly for the 360, or you'll need a BM weighted flex.
Easy to tell if it's a lockup. Pull the converter and look at the shaft. A shaft with spines to the end is non-lock. If it has a smooth nose "looks like" a manual gearbox pilot it's a lockup
Below, non lockup at left
Excellent information I will pull the converter just to make sure its a non lockup. The converter in it now DOES have the weight on it which was one of the first things I checked after I found out about the weighted converter 360s needed. I have the Numbers off the side of the tranny if anyone wants to give them a shot? Tried that here once and no one could tell me much. Also took a screenshot of a transmission assembly and replacement part site and the first long number came up which reads it as a small block 4x4 non lock up but doesn't say much else.
Yes should be pretty much a bolt up but ensure the converter is weighted properly for the 360, or you'll need a BM weighted flex.
Easy to tell if it's a lockup. Pull the converter and look at the shaft. A shaft with spines to the end is non-lock. If it has a smooth nose "looks like" a manual gearbox pilot it's a lockup
Below, non lockup at left
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