Which would you use: 489 or 742 case

[covert]

Hi,

I have a nice, clutch type suregrip out of a donor car, sitting in a 742 case.  My car has a 489 case, with open differential.

Both have 2.73 gears (not useful to me)

I've already lined up a professional shop to switch out the ring and pinion, and and install in the car.  So my question becomes which case should I use (which determines which ring and pinion I order).

-  I use the 489 case -- so I have to take out the center section of 742, get them to install and setup the new gears and the center suregrip section into the 489 case.  I'm left with 742 case, and open center section (separate pieces, cause I'm not paying them to put those back together)

- I use the 742 case.  They just rebuild the 742 with the new gears.  I'm left with complete, setup and functional 489 case with working open center section.

From what I've read, either case should be fine -- as these are both the "good" cases.  I guess the 489 is technically a little stronger, but for the power of my engine, the 742 would be solid too.  The advantage of using the 742 case is I still have a functional 489 (read, I can sell on ebay, and get a little bit of my money back)

Which would you do?

Thanks,
Covert

[cowboy]

 

[hemiken]

I am sure i read somewhere that you can not interchange the internals with these two cases ?    Wait and see if someone else chims in to verify this. 

[Chryco Psycho]

ok the 742 is the best carrier to use , it is stronger than the 489 & already has the sure grip , the gears can actually be swapped from the 742 into the 489 carrier with a different pinion brg otherwise each gearset is unique to its carrier

[hemiken]

Thanks C/P.  I was not 100% sure on that.

[cowboy]

-
But the suregrip is interchangeable between all of them, rigth..

[Chryco Psycho]

yes

[FJ5_440]

  put the new gears in the 742, and keep the 2.76 centersection to slap in for the powertour

[covert]

Cool -- OK, 742 it is. 

Thanks,
Covert