727 Converter Question

["Dart67"]

I am not to versed on torque converters.

I have two converter a friend has given me.

One has a small diameter pump drive. I "ASSUME" this is a 904 converter.

The one I have an interest in has a larger diameter pump drive. I "ASSUME" this is a 727 converter.

I do not know if it is from a small block or big block 727.

It does have a small about 3/4" square sheet metal square tab spot welded to the case.

That kind of leads me to believe it came from a external balance engine.

Can this converter be used behind my big block if it is from a small block.

If so, should the spot welded tab be removed.

I want to replace the COAN Billet 3800 stall with a more street friendly converter.

Thanks,

Herb

 

[Jimmy428]

The weight you are referring to is necessary for overall balance of the converter itself to keep it a neutral balance converter.

An external balance converter will have big weights on either side of the drain plug. If this is the case, knock them off if you don't need them and you're golden.

As for the 727 vs 904, I'm sure someone has a more scientific way of telling you the difference, but in my experience, just try to install it. You'll find out very quickly if it works or not. Be careful you know what it feels like for it to be installed on the splines, otherwise I hope someone else chimes in to help better identify the converters.

As far as between small block and big block, no difference other than the flexplate. The same unit stalls differently depending on the power output of the engine in front.

Oh and this should go without saying, always be cautious with unknown converters. If you must use them, try to drain via drain plug and flush with new ATF to prevent any debris and general crud from getting into your trans.

Hope this helps. Good luck:burnout:

 

[bOb shingler]

in addition to the above, the vertor bolt tabs need to be about 1/2" behind the front of the bell housing edge when seated correctly. use the one with the larger diameter pump drive.

 

[transman]

The weight you are referring to is necessary for overall balance of the converter itself to keep it a neutral balance converter.

An external balance converter will have big weights on either side of the drain plug. If this is the case, knock them off if you don't need them and you're golden.

As for the 727 vs 904, I'm sure someone has a more scientific way of telling you the difference, but in my experience, just try to install it. You'll find out very quickly if it works or not. Be careful you know what it feels like for it to be installed on the splines, otherwise I hope someone else chimes in to help better identify the converters.

As far as between small block and big block, no difference other than the flexplate. The same unit stalls differently depending on the power output of the engine in front.

Oh and this should go without saying, always be cautious with unknown converters. If you must use them, try to drain via drain plug and flush with new ATF to prevent any debris and general crud from getting into your trans.

Hope this helps. Good luck:burnout:

X2 on cleaning the converter. Make sure hub has a mirror like finish on it, otherwise you're looking at a possible leaker.
The 904 has the smaller diameter hub.
The weight as mentioned is a factory weight just to balance the converter.
From 1967-1978 all 318-383-400 engines with a steel crank,no weights on the converter, while engines with a cast cranks had weights.

 

[fishy68]

Another consideration is there are 3 different spline counts on 727's transmissions. Through 66 they were 19 spline. Then they went to 24 spline in 67. Then there was the rare lockup trans that used a different splined input shaft yet. I think it was 23 spline but not positive. Gotta make sure that's right for your trans.

 

["Dart67"]

Thanks for all the replies and good helpful information.


I have guest from Illinois right now.

When I have a chance I will give the converter a better inspection.

Thanks again,

Herb