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Techical Discussions => Tech- - DRIVE TRAIN => Topic started by: Shawn on December 29, 2008, 05:02:07 PM

Title: 8 3/4 742 case big block 727 trans
Post by: Shawn on December 29, 2008, 05:02:07 PM
 I am planning to swap a 2.76 gear with another ratio. What would be a good gear for the street ,is a 3.91 or 3.73 to steep. Can anyone tell me where a yukon ring and pinion is manufactured. would like to keep it USA if possible. thanks
Title: 8 3/4 742 case big block 727 trans
Post by: Leaburn Patey on December 29, 2008, 05:40:59 PM
hey grasscat1965 WELCOME!!
What car do you have??
Depending on your complete package (cam,stall speed,tire size) the rear gear ratio has to work with everything else,IMO.
3.91's behind a slant six you can pull houses all day.Same gear behind a 440 can be fun between stop lights.
 
A common street gear and still drive on the highway with the occasional armdrop event 3.23's or 3.55's work well across the board.
 Not sure where Yukon gear  products are made since I never had  the oppourtunity to use there stuff.
CBarge2008-12-29 22:45:21
Title: 8 3/4 742 case big block 727 trans
Post by: Steve on December 29, 2008, 06:18:27 PM
Hey there  Welcome!
 
Yes we need to know what you have and wht you are looking to get out of the car.
 
373 is usually found in the 3rd Generation Dodge Pick Ups.  Not sure if that is available in an 8 3/4 rear, unless that is what you have in the car.
Title: 8 3/4 742 case big block 727 trans
Post by: Shawn on December 29, 2008, 06:32:53 PM
I have a 68 Charger with a 400 engine,  727 trans, mild rv cam, no stall, tires are P245/60R15 (25 inches from bottom to top).  3.23 is not available for a 742 case 3.55 is available from  Yukon  if I replace the yoke. 3.73 is available with a coarse spline no yoke required. Just looking for something fun to drive around town. Gear ratio now is 2.76.
Thanks a lot.
Title: 8 3/4 742 case big block 727 trans
Post by: Steve on December 29, 2008, 06:45:23 PM
OK  That's good info. . .
 
I forgot about the 3.73 in the corse spline. 
 
Try this guy. . . .
 
 
Carl Montoya
JTS Parts & Accessories
5980 Goodwin Rd
Cashmere, WA 98815
www.justdifferentials.com (http://www.justdifferentials.com/)
carl@justdifferentials.com (http://mailto:carl@justdifferentials.com)
509-888-AXLE (2953) ext. 113
866-399-7532 fax
 

Title: 8 3/4 742 case big block 727 trans
Post by: Shawn on December 31, 2008, 04:52:26 PM
Thanks for the info. I found two sources for 3.55 gears made in USA.   
                     Moser engineering         U.S gear (Strange)            
Title: 8 3/4 742 case big block 727 trans
Post by: Shawn on December 31, 2008, 05:02:00 PM
Forgot to ad that no additional parts (yoke) will be needed. Both replacement pinions have course spline .    BONUS    
                                                         Thanks                                      
Title: 8 3/4 742 case big block 727 trans
Post by: Steve on December 31, 2008, 05:27:12 PM
Yes
 
Try too stay away from Yukon.  Not because they are Canadian. . . They're gears are nice, but they have trouble converting Can to US measurements.  Had a Hello a time with a set of their gears last year.
 
2 years ago I used their Posi set-up.  That was a problem child too.  It wasn't until later I found out they had a QC problem with dirt getting into the clutch plates.  When I spoke to them they said they had a dirt problem in some of the units and would send me a new set so I could repair it.  For the tune of $50.00 + shipping that is.
 
POLARACO2008-12-31 22:27:33