70 Javelin with mopar 8 3/4

rich freitag · 11-18-2017, 01:30 PM

I am building a 70 Javelin forNHRA
stocker ,I installed a mopar B body 8 3/4 rear and the center section it is offset.Will this cause any problems with the stock drivetrain.I am running a AMC 360 with a 727 trans.Should it be 0 offset ?

Rod Greene · 11-18-2017, 02:21 PM

Mopar offsets the drive train 1 inch to the right (passenger side). If AMC has the drive train centered that is where the pinion should be. You should measure and set the pinion so there is no side to side angle. The only angle you should have is down. If you haven't spent much on the 8 3/4 I would put a Dana 60 in the car. It is stronger and faster.
Good luck.

Myron Piatek · 11-18-2017, 03:03 PM

If building a class car and it's available, a 904 is faster than a 727. Chrysler did some testing back in the '70's and it was about .15, all else being equal, plus you'll have the option of a less expensive 2.74 low gear set from a later trans.

General question - since the pinion is offset in Mopars with similar drivetrains & suspension, would matter if it was in an AMC or Mopar body?

Coleydog · 11-19-2017, 10:29 AM

Just to clearly, an 8-3/4 is not offset (center section) it's the pinion. Whereas the Dana is offset (center section) because the pinion is not as offset as the 8-3/4. I would like to see how many tenths of a horse power you would lose by being "not centered" when the up and down movement (car separation) is astronomical. Now if you're running a four link, go for it.
Mike

Dwight Southerland · 11-20-2017, 09:36 AM

I would use a Dana 60 rather than the 8 3/4.

amxron · 12-01-2017, 03:22 AM

An 8.75 isn't much stronger than an AMC-20 with 1 piece axles.
I ran for years with Henrys Axles, an AMC left hand thread TwinGrip & 4.44's
and the tubes welded in. (390/4sp D/Stock).

Ron.

11-18-2017, 01:30 PM	#1
rich freitag Junior Member Join Date: Mar 2008 Location: cicero n.y. Posts: 29 Likes: 7 Liked 0 Times in 0 Posts	70 Javelin with mopar 8 3/4 I am building a 70 Javelin forNHRA stocker ,I installed a mopar B body 8 3/4 rear and the center section it is offset.Will this cause any problems with the stock drivetrain.I am running a AMC 360 with a 727 trans.Should it be 0 offset ? __________________ Rich Freitag 1440 SS Last edited by rich freitag; 11-18-2017 at 09:16 PM.

11-18-2017, 02:21 PM	#2
Rod Greene Senior Member Join Date: Mar 2002 Location: TN Posts: 530 Likes: 420 Liked 242 Times in 81 Posts	Re: 70 Javelin with mopar 8 3/4 Mopar offsets the drive train 1 inch to the right (passenger side). If AMC has the drive train centered that is where the pinion should be. You should measure and set the pinion so there is no side to side angle. The only angle you should have is down. If you haven't spent much on the 8 3/4 I would put a Dana 60 in the car. It is stronger and faster. Good luck. __________________ Rod Greene Real men shift for them selves. Slowly working on TA Challenger for D,E/S and a 72 Challenger for SS/K, L as if I don't have enough other projects.

11-18-2017, 03:03 PM	#3
Myron Piatek VIP Member Join Date: Nov 2001 Location: Florida Posts: 1,542 Likes: 34 Liked 138 Times in 51 Posts	Re: 70 Javelin with mopar 8 3/4 If building a class car and it's available, a 904 is faster than a 727. Chrysler did some testing back in the '70's and it was about .15, all else being equal, plus you'll have the option of a less expensive 2.74 low gear set from a later trans. General question - since the pinion is offset in Mopars with similar drivetrains & suspension, would matter if it was in an AMC or Mopar body? __________________ LOCOMOTION Racing

11-19-2017, 10:29 AM	#4
Coleydog Senior Member Join Date: Jul 2014 Posts: 569 Likes: 36 Liked 53 Times in 38 Posts	Re: 70 Javelin with mopar 8 3/4 Just to clearly, an 8-3/4 is not offset (center section) it's the pinion. Whereas the Dana is offset (center section) because the pinion is not as offset as the 8-3/4. I would like to see how many tenths of a horse power you would lose by being "not centered" when the up and down movement (car separation) is astronomical. Now if you're running a four link, go for it. Mike Last edited by Coleydog; 11-19-2017 at 10:31 AM.

11-20-2017, 09:36 AM	#5
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 2,000 Likes: 64 Liked 777 Times in 193 Posts	Re: 70 Javelin with mopar 8 3/4 I would use a Dana 60 rather than the 8 3/4. __________________

12-01-2017, 03:22 AM	#6
amxron Junior Member Join Date: Jan 2007 Location: Md Posts: 23 Likes: 0 Liked 1 Time in 1 Post	Re: 70 Javelin with mopar 8 3/4 An 8.75 isn't much stronger than an AMC-20 with 1 piece axles. I ran for years with Henrys Axles, an AMC left hand thread TwinGrip & 4.44's and the tubes welded in. (390/4sp D/Stock). Ron.