Stock TQ or aftermarket

[Nacho-RT74]

some stock TC rates from some late FSM... so, you can get a nice stall rate to match your assembly from a stock piece... as I have told, maybe not so efficient like an aftermarket one, but, once again, will depend of the useage and needs.

Now, is hard to define which one is what one since they are not marked with PNs

[Canadian1968]

the hughes comes with 5/16 the HD comes with 7/16. these are just the bolts that connect the plate to the converter correct ?

So if I go out put my foot on the brake hit the gas ... what the rpm goes up to before it wants to break the tires loose is stall ?  Is this a semi accurate method to see what I currently have ?

[firefighter3931]

Here is some parts to look at for the converter install :

Flex Plate : http://store.440source.com/SFI-APPROVED-Solid-Flexplate-6-bolt-Neutral-balance/productinfo/200-1084/

ARP fastners in 5/16 & 7/16 : https://www.summitracing.com/search/part-type/torque-converter-fasteners/transmission-type/torqueflite-727?N=400295%2B4294910484%2B4294945319&SortBy=Default&SortOrder=Ascending&tw=torque%20converter&sw=Torque%20Converter%20Fasteners

To test stall speed :

Put the trans in 3rd gear and bring the car up to 10-15mph and mash the pedal while looking at the tach. The converter will flash up to the stall speed.

If the trans has a stock valvebody you will need to disconnect the kickdown linkage (temporarily) to keep the trans from kicking down when you hammer the pedal in drive.


Ron

[Canadian1968]

thanks for all the help.

the 5/16 and 7/16 are just the size of the mounting bolts . and then depending on size of converter determine the "bolt circle " correct ?

[justcruisin]

Correct - converter to flex plate. If you get the flex plate Ron suggested you are good to go which ever way you go. Personally I would go with a converter with the 7/16" bolt pads  but for your combo the 5/16" will be OK.

[John_Kunkel]

Surprisingly, there are actually only two 727 converters in Nacho's pic. All of the 10 3/4" converters are the same and all the 11 3/4" converters are the same, the difference in stall speeds is due solely to the difference in power input.

The vaunted Hemi converter is the exact same as a 340/HP 383 of the same year except for the drive bolt size. Again, the difference in stall speeds relates to engine size.

[firefighter3931]

Correct - converter to flex plate. If you get the flex plate Ron suggested you are good to go which ever way you go. Personally I would go with a converter with the 7/16" bolt pads  but for your combo the 5/16" will be OK.

As JC stated above....the 440 Source flexplate is drilled for both the small and large converter bolts in the 10 inch bolt pattern. If you can get the bigger 7/16 bolts as an option just do it. 

I use blue Loctite on converter bolts...allways   

Surprisingly, there are actually only two 727 converters in Nacho's pic. All of the 10 3/4" converters are the same and all the 11 3/4" converters are the same, the difference in stall speeds is due solely to the difference in power input.

The vaunted Hemi converter is the exact same as a 340/HP 383 of the same year except for the drive bolt size. Again, the difference in stall speeds relates to engine size.

Very true....the engine's torque output will ultimately determine the stall speed. The same converter behind two different motors will have different stall speeds. The lower the output, the lower the stall and conversely the higher the output, the higher the stall 



Ron

[Nacho-RT74]

Surprisingly, there are actually only two 727 converters in Nacho's pic. All of the 10 3/4" converters are the same and all the 11 3/4" converters are the same, the difference in stall speeds is due solely to the difference in power input.

The vaunted Hemi converter is the exact same as a 340/HP 383 of the same year except for the drive bolt size. Again, the difference in stall speeds relates to engine size.

True, never checked that before on my 74 parts catalog!. It barelly shows 3 or 4 diff TC PNs, and some of them are due the forged or cast setup

[John_Kunkel]

The pic you posted is from the '75 FSM...pretty much the same for the smog years. After '77 all gasoline 727 converters were 10 3/4".

[Nacho-RT74]

half of the ones on my catalog are 28XXXXX, so 67/68 PNs

[Canadian1968]

Bring this thread back to life!  I have narrowed my options down to two Converters.  The Hughes 24-2500 Stall 10" bolt circle with 5/16 bolts.  OR  TCI Breakaway 24-2600 stall 11" with 5/16

Would there be really any difference between the 10 and 11 as the stall specs are basically identical. ?

[c00nhunterjoe]

With the 3.23s the 11" will "feel" tighter until harder on the throttle

[Canadian1968]

So better street manours ? At any point would the 10" have an advantage ?

actually I need to get more exact info ,different companies seem to use different number for what is actually same size converter .  The hughe's has 10 bolt circle the tci is advertised 11" converter but I think may still have the 10" bolt circle .  The other tci converters are advertised as 12" converter which would the factory bolt circle

[c00nhunterjoe]

If it were my car, i would run the 10". Others will say run the 11. The torque output of your current engine, i doubt you will notice much difference in the two. The only time you would really notice it is in high gear at lower speeds prior to kickdown. The 10"will flash higher then the 11, but on a very tame engine, we are talking 200 rpm maybe?

[c00nhunterjoe]

Different trannys, but the theory in this test is the same as in this discussion. Playing around with my truck and the torque management features. Long story short- no reduction in power in high gear so i can really use the torque of the motor to play with the converter. This is a 4l80, with a factory high stall converter rated at 2500 rpm stock. Engine is a 6.0 with no cats, full 3 inch dual exhaust and a custom program. 4.10 gears a 33 inch tires. When driving the truck normal, it behaves like a standard converter, but when you force it, it will flash at almost 3500 now.

https://youtu.be/zuJDkj3c774
https://youtu.be/V8zb0KtF1QQ