727 Torque converter in 904? If not, what should I get?

[BooGTS]

Hi,

Have a 67 273 car, and we are putting in a 340. Car has the original 904 and (according to what I've looked up) 1800 rpm stall. Have access to what should be a 2200 stall converter for free, but it is from a 727. It doesn't seem like this will work, but I couldn't find a direct answer for this.

If we need to buy a torque converter, I've heard Coan are good and we should just get a 2200 RPM stall?

I'd take a 4 speed setup as well, ha.

 

[replicaracer43]

Converters are different, call a converter builder and get one built for your car, money well spent imo

 

[Hellrats]

A 727 converter will not fit in a 904. The 340 came from the factory with a 2400 stall converter. Stall speed should be considered after you pick the camshaft and rear gears you are going to run.

 

[67Dart273]

Be sure to check the converter pilot/ register, the earlier engines are smaller than than when? 68/ later?

 

[BooGTS]

Going to be tricky to know the cam rpm range since we are getting a 340 that has an unknown cam already in it. PO describes it as "mild" but no I have no idea what that means. I assume a bit higher than stock range, so possibly 3000 stall would be appropriate. Only mods are an edelbrock carb, mid-rise aluminum intake, the cam, and long tube headers. Sent a form into Coan with all the specs of the engine and car that we know and I'll see what they say.

 

[transman]

A 727 converter will not work in a 904. If you measure the diameter of the converter hub(the part that goes into the pump), you'll see that the 727 is a different size than the 904 hub. Make sure you tell Coan that you're using a 904 transmission and it will be going behind a 340. As Hellrats said, the stall on a 340 converter is about 2400 RPM, and with the minor modifications to the engine, and I think it should suit you just fine. The catch though is the unknown specifications on the cam. Unless there was a dyno sheet available, our performance converter/engine guru always wanted the cam specs were important to ensure the customer got the right converter.