8 3/4 posi from 71 truck into a 69 charger

[69dodge383]

I have a semi posi in my 69 charger 8 3/4 rear. i saw a guy with a posi rear 8 3/4 from a 71 dodge truck. can i swap the center sections and make my rear a posi? wanting to know if there are any problems with this. trying to also reuse the 3.23 gears that are in the car now

Thanks

Doug

[Chryco Psycho]

easily done , you can either swap the whole carrier with the gears fromt he truck or you can install the sure grip unit into your gear set . Make sure you measure the back lash between the gears if you are swapping the sure grip into your gear set so it can be reset .

[Cooter]

unless you have access to alot of specialty tools to set backlash, bearing preloads, pinion depth, etc. I'd reccomend you find someone to set this up for you. No, you cannot do this in your home garage, in about 2 hours, with simple hand tools, and be riding the same night.

[John_Kunkel]

What's a "semi posi"? 

[69dodge383]

sound like in my best interest that i should buy a center section with the ring and pinion that i want already on it. i see alot of them on ebay. according to cooter, this is a heck of a project. yes?

[squeakfinder]

     Your wanting to place the SURE GRIP carrier from the pickup into your center section? If the rear end on your Charger isn't making any noise or the pinion seal isn't leaking you'll just be swapping ring gears and setting up backlash.
       You'll need a plunger style dial indicator with a magnetic base. And a spanner wrench to adjust backlash (it's not that hard to make a spanner wrench).
      Here's a crash course....

http://www.moparmusclemagazine.com/howto/mopp_0308_mopar_rear_end_gears_set_up/index.html

                       

[69dodge383]

I have found some center sections on ebay that are in good shape, sure grip and have gear already installed on them. I havent checked but think I have a 489 my 69 charger. I found one i like with 355 gears, sure grip and it is a 741 case. Does it matter if I go from a 489 to a 741?

[Cooter]

The "741" is a light duty chunk....The "489" is a heavier duty chunk. If your not making much power [READ torque], then you'll be fine, but otherwise, your actually going backwards. That's why the "741" unit is priced affordably. The higher priced "489" units are the way to go with the 8 3/4.

[Chryco Psycho]

watch the Yolk size also , there are 2 sizes of U loint , 7160 - 21/8 " inside the ears , 7190 2 5/8 inside
there is a conversion U joint available if needed

[69dodge383]

@Chryco Psycho - I will measure the yoke over the weekend when I have time. The guy sold the truck rear. So I am back to looking for a center section. I want to get my driveline ready before I do the engine swap.

@Cooter - There will be plenty of torque, I am either going to be building an engine like this or buying this around the summer time. Im thinking I am going to need to go with the 489. Yes?

http://www.blueprintengines.com/index.php/chrysler-493-bp4931ct

[Chryco Psycho]

the 742 is the best , the 489 is the next choice & the 741 is last, however if the tires spin I bet you will not hurt any of them , put on slicks with traction & it may become an issue

[Cooter]

I personally think the Dana 60 is "The best" factory rearend, but that's just me.

[Chryco Psycho]

true but I cannot fit the Dana gears into a 83/4 housing LOL

[AKcharger]

May I suggest not messing with your 3:23 unit and just find a complete center section with a working sure grip? This way not only will everything work right but you can swap out centers if you want gas mileage. They aren't hard to find and the swap is easy enough

http://www.dodgecharger.com/forum/index.php/topic,2077.msg25944.html#msg25944