Baby 904 vs BW35

[valitank]

Hi All,

Just a few questions...

Im planning on an injected 2.6 turbo astron ii (either gn with magna head) or plain magna modded to suit rwd. What box has better strength? are the ratios the same? Im after something that can handle power but cruise if possible lol. with a 2.0 and bw35 the ge sits on close to 4000 rpm at 110kph at which point is screaming its arse off lol. If i go 904 what do i need for it to go into a ge? will the kickdown lingages need to be modded to suit the efi intake?
Thanks

[amgis_obrut]

rpm will be the same @ 110 kph

[BAD-SIG]

Just in case anyone else comes across this, the very first GE Sigmas had the Torqueflite MA904A. The main differences are:

BW35: stall = 2500-2600rpm

1st = 2.39
2nd = 1.45
3rd = 1.00

Torqueflite MA904A: stall = 2200-2650rpm

1st = 2.45
2nd = 1.45
3rd = 1.00

These were taken from the factory Chrysler workshop manuals.

To do this swap, you will need the trans, flex plate, torque converter and tailshaft. I think the tailshaft bolt-up flange on the diff might be different too, as the GE Sigmas that had the Torqueflite all had the "Jap diff" while the later models had the BW diff.

[Cottees]

In my GN, I have a BW40. For the kickdown, I attached a steel cable from the kickdown cable from the trans, and hooked the other end to the standard TR/TS throttle body. I can't find a pic of that at the moment. It worked well, till that cable snapped.



Here is a graph I prepared earlier:

That is with a 3.42:1 rear diff, 175/75 14 tyres and the BW40 gears as follows:
1st- 2.39:1
2nd- 1.45:1
3rd- 1.00:1

Stall speed 2,470-2,670 rpm