340-727, what rear?

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swing69

fightin' socialism
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73 Dart Sport. was a 318/904/7.25. It will be a 72 340/727 with a choice of rears:

A) 8.25 SG w/3.55 gears (cone style)
B) 8.75 SG w/3.55 gears (741 case, clutch style)
C) 8.75 SG w/3.23 gears (489 case, cone style)

#1 Which rear would you pick and why?
#2 What stall converter with your pick?

More info: 98% street car, rotisserie resto, frame conn., Nice 05 Magnum seats and a LOUD stereo. 15x7s all around, front sway bar, Non AC dash / htr swap.

Car to be sold in June 08 when completed.
 
If I would have these on hand, I would use the 8 3/4 "489" (stonger, larger pinion dia), but would prefer the clutch type (easier to rebuild) over the cone with the 3:23 gears (good all around) unless you plan on racing it alot.

For the torque converter, it all depends on the engine build, mostly the cam used.

My .02, all the best.
 
I have that rebuilt 440/727 that no one wants, so if the shop stays open, it would be nice to have the 489-3.23 for the NEXT BB A body car.

The cam will be the summit 6901, which I'm told is similar to the stock OEM 340 cam grind. intake, stock 340 for 72.
 
none. the driveshaft I have is a 904/7.25.
I have 727 and 904 slip yokes kicking around.

Tranmission question:

any preference on the 904 vs. SB 727??
 
swing69 said:
73 Dart Sport. was a 318/904/7.25. It will be a 72 340/727 with a choice of rears:

A) 8.25 SG w/3.55 gears (cone style)
B) 8.75 SG w/3.55 gears (741 case, clutch style)
C) 8.75 SG w/3.23 gears (489 case, cone style)

#1 Which rear would you pick and why?
#2 What stall converter with your pick?

More info: 98% street car, rotisserie resto, frame conn., Nice 05 Magnum seats and a LOUD stereo. 15x7s all around, front sway bar, Non AC dash / htr swap.

Car to be sold in June 08 when completed.
Click to expand...

If I was planning to sell the car I'd put the 8.25 in it & hope it held up. Should be OK with the automatic in front of it. I'd save the 8.75 stuff for myself.

Have to say that having it done by June 08 is setting a pretty lofty goal. I'd try for June 09. :-D
 
It will be completed. We've got a car show scheduled, so it NEEDS to be done by then! We're down to bodywork now. it should go pretty fast.

340-auto into a 8.25 should be fine. Isn't a 8.25 what all the factory A bodies with 340s/360s came with after 1971 ? or was is 73? either way, I'm sure it will hold up fine.
 
I'd stay with the 904 properly built it can handle anything you'll throw at it,i'm still running the one my duster came with from the factory 318/904 car,now behind my 416 or 360 of coarse it built to handle all the power...
 
I would use the 727 trans and the 8.25 rear (especially if it has big bolt pattern). You will probably have to either shorten or just replace the driveshaft, even if you used the 904 transmission.

I had to replace mine in my cuda when I changed out the 7.25 rear with an 8.75 rear, because the larger rear places the yoke farther forward. I would bet a driveshaft for a car with an 8.25 rear is a bit shorter than one for a 7.25 rear.

Bob
 
Not sure how long it's been in there but it's still going strong. 8 1/4's aren't that weak. If you plan to race the car, go with the bigger rear but for street/strip use, the smaller is fine. If you plan on running slicks, then go with the bigger rear, otherwise, keep it near stock.
 
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