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Technical => Roo Man's Room => Topic started by: JeffV8 on September 08, 2014, 08:17:10 PM

Title: Which center section?
Post by: JeffV8 on September 08, 2014, 08:17:10 PM

What one should I use in my 1966 Woody dragster? A 741 742 or 846 for that era.

Thanks
Jeff

Title: Re: Which center section?
Post by: Pipe Dreams on September 09, 2014, 04:02:46 AM

742 would be my first choice. Second would be a 489.

Title: Re: Which center section?
Post by: dreracecar on September 09, 2014, 08:26:11 AM

742 is better than the 489 although both will work fine and if its just a Cacklecar anyone of the three, although I dont know what spline is on the pinion of the 741 and if a coupler is made for it, if it is different.
The 742 has an 1 3/4"dia pinion shaft vs the 489 1 7/8 which might make you think the 489 is better but the case is the the pinion bearings are larger in the 742 so they take the load better.
What also makes the 742 better is that the pre-load is set with shims and the nut is torqued in place whereas the 489 is a crush sleeve and you tighten the locknut untill preload is met.

Title: Re: Which center section?
Post by: JeffV8 on September 09, 2014, 09:33:35 AM

741 has a 1 3/8 pinion.  I found one for $100 I guess I will pass on it.

Thanks for the info

Jeff

Title: Re: Which center section?
Post by: janjon on September 09, 2014, 07:48:07 PM

If I wasn't such a smart feller, though some would say I'm just a fart smeller, I would have no idea you were talking 'bout Mopar 8-3/4" rears.

Title: Re: Which center section?
Post by: JeffV8 on September 09, 2014, 08:33:40 PM

Until you mentioned it I didn't realize I didn't say mopar. But like you anyone in the mopar rear ends know what I was asking   lol

Title: Re: Which center section?
Post by: slingshot383 on September 10, 2014, 03:52:06 AM

If you need a new pig, look into the aluminum one that Mopar Performance sell.  It's based on the 742 case, and is lighter.  Is your 8 3/4 a full floater?  The one in my Woody car was, lots of fun finding the bearings and seals.

Title: Re: Which center section?
Post by: George on September 10, 2014, 07:39:08 AM

I have been putting the iron 742 to the test in our 1700# blown SBC FED. Last time out went 4.61,4.59,4.59 with two .99 60' ( 1/8 mile). Leaving off the trans. brake at 5400 . If there were more season left I would replace the 12 X 33 with some 14". Probably build a Ford 9" for the car this winter.