Difference between stock 727 and 904 Converters?

[Lucas Ramm]

Hello All wondering if there is a difference between stock 727 and 904 Torque Converters. Pulling my transmission out alone i stripped one of the converter bolts out and need to put another in. I have a handfull of 727s in the garage but didnt want to put something there that didnt belong/work. Obviously it has to bolt up to flex plate but thats pretty easy to tell if it will work or not. Any info or advice is welcome.

Thanks,
Lucas

73' Charger with built 318
54' New Yorker Dual Quad 331 Hemi

 

[AR67GTX]

Don't take any of this as gospel without doing a little checking, but if it has 5/16 inch bolts you could overdrill and tap the converter for 3/8 inch bolts if you like the converter. I think Chevy used 3/8 inch converter bolts so finding a thin-head 3/8 inch AARP bolt probably isn't much trouble. Your flex plate bolt holes are probably not much shy of 3/8 inch now and a small reaming would open them up. Pretty sure based on recently shopping for a new 727 converter that they don't interchange with a 904 converter. I think the splined input shafts are different dimension.

 

[Darter6]

Yes 727 and 904 converters do not interchange.3/8'' converter bolts Mopar style can be had thru ARP.

 

[Greg Ducato]

The stock bolt size on either the 904 or 727 is 5/16. If you have the thick converter pad you can drill and heli coil the pad to make a repair pretty easily. If you have the thin pads it is not so easy as you need a bottoming tap for the heli coil set and even then it will be very difficult to thread to the bottom. The 727 and 904 will not physically interchange in any way.

 

[Lucas Ramm]

Great thanks for the info everyone! Just finished the rebuild on the tranny last night. got the new flex on today. going to dig through the dozen or so converters I have in my building. Or does anyone have any after market suggestions? build is on a budget as I am 20. looking to spend 250 or less

Regards
Lucas

 

[AR67GTX]

I bought a Hughes converter for my A727 this winter, as it seemed to be the best value for something with decent quality and reputation. I believe it was under or right at $250. I don't have my car back on the road yet to tell you how it performs.

 

[Lucas Ramm]

I bought a Hughes converter for my A727 this winter, as it seemed to be the best value for something with decent quality and reputation. I believe it was under or right at $250. I don't have my car back on the road yet to tell you how it performs.

ive looked at couple hughes converters ive also heard good things about boss hogs.

 

[Lucas Ramm]

The stock bolt size on either the 904 or 727 is 5/16. If you have the thick converter pad you can drill and heli coil the pad to make a repair pretty easily. If you have the thin pads it is not so easy as you need a bottoming tap for the heli coil set and even then it will be very difficult to thread to the bottom. The 727 and 904 will not physically interchange in any way.

i would worry about the sturdyness of a helicoil in a torque converter. i feel like it would be under too much pressure and would rip out. I work in an autoparts store and people often times bring in sparkplugs from 2 and 3 valve tritons with the helicoil repair still on the plug