Mopar 8 3/4 VS 8 1/4

magnumv8 · 10-06-2009, 08:50 PM

I've run an 8.25 for years and never had an issue with it 12 sec.vehicle....over 1000 passes with the original suregrip and 4.56 gears (they are getting replaced now)..... Moser made me a set of alloy axles when I first built it and recently I picked up a locker for it for the rebuild....I guess the the main issues would be axle retention and the fact that you can run a little shorter driveshaft with the 8 3/4 allowing more rpm before driveshaft issues....

Phillip marvetz · 10-07-2009, 12:50 AM

I have been using the 8 1/4 all season with out any issues and I'm sure it is plenty strong enough for what I use it for, I'm wondering if the 8 3/4 is more efficient or not. I don't really have any concerns about the ease of gear changes, Is it worth the hassle of changing the hole assembly ET wise?. Hey John, have you swapped out the rear in the mirada yet? Any one have a phone number for Loge? Sound's like he would have experiance to give me the right answer.......

GTX JOHN · 10-07-2009, 03:27 AM

Sold the Mirada to North Carl. family.. beleive they are still running the 8.25 with no problem. I would research gear availablity ... have not seen any gears past 4.50 since 1980. Mopar in its race seminars did not encourage us to run then in high HP stockers even in 1970's.

10-06-2009, 08:50 PM	#1
magnumv8 Member Join Date: Feb 2009 Location: Coraopolis, Pa. Posts: 172 Likes: 0 Liked 0 Times in 0 Posts	Re: Mopar 8 3/4 VS 8 1/4 I've run an 8.25 for years and never had an issue with it 12 sec.vehicle....over 1000 passes with the original suregrip and 4.56 gears (they are getting replaced now)..... Moser made me a set of alloy axles when I first built it and recently I picked up a locker for it for the rebuild....I guess the the main issues would be axle retention and the fact that you can run a little shorter driveshaft with the 8 3/4 allowing more rpm before driveshaft issues....

10-07-2009, 12:50 AM	#2
Phillip marvetz Senior Member Join Date: Oct 2008 Location: Lynden ,WA Posts: 820 Likes: 0 Liked 3 Times in 3 Posts	Re: Mopar 8 3/4 VS 8 1/4 I have been using the 8 1/4 all season with out any issues and I'm sure it is plenty strong enough for what I use it for, I'm wondering if the 8 3/4 is more efficient or not. I don't really have any concerns about the ease of gear changes, Is it worth the hassle of changing the hole assembly ET wise?. Hey John, have you swapped out the rear in the mirada yet? Any one have a phone number for Loge? Sound's like he would have experiance to give me the right answer.......

10-07-2009, 03:27 AM	#3
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,733 Likes: 2,802 Liked 2,486 Times in 697 Posts	Re: Mopar 8 3/4 VS 8 1/4 Sold the Mirada to North Carl. family.. beleive they are still running the 8.25 with no problem. I would research gear availablity ... have not seen any gears past 4.50 since 1980. Mopar in its race seminars did not encourage us to run then in high HP stockers even in 1970's.