82 what rear gears
Tech Contributor
Joined: Aug 1999
Posts: 15,173
Likes: 3,982
From: Connecticut, USA
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
#1 if you like to step on the gas (full throttle) for 2-3 seconds and then off the gas gears 4.11 or 3.73 with the T56 close ratio.
#2 if you like track days then it depends on the track. reduce gear shifting. 4.11 & 3.73,3.55 a lot of shifting and may hit engine red line before the end of the straights.
#3 auto cross probabily doesn't matter , 2nd gear most autocross tracks with 3.08 or 3.36 or would be 3rd with 3.55, 3.73 , or 4.11
#4 street /highway driving 3.08 , 3.36 less shifting best gas mileage for highway, engine can easily deal with any diff gear.
most like #1.
my 78 is with a LS3 / 480 T56 Mag close ratio. Used for trackdays / street / highway. Have both 3.08 & 3.36 diff's both are fine.
Main question would be Based on GTR1999 how well it can handle the application use.
Last edited by cagotzmann; Jun 28, 2023 at 10:04 PM.
Safety Car
Joined: Nov 2008
Posts: 3,717
Likes: 551
From: Seattle Washington
A general hot rodders rule is to use the factor of 10 for the first gear. In other words take 10 and divide it by your 2.66 first gear and you will get 3.75 so that will be your rear end ratio. If you have a small displacement engine with a high RPM you may want to use a factor of 11. If you have a large displacement engine with a low RPM you may want to use 9. And of coarse what are you going to use it for as mentioned above. I for see you doing an Iron Pumpkin conversion on your Dana 44.
Melting Slicks
Joined: Nov 2006
Posts: 3,409
Likes: 1,821
From: Apple Valley, MN
Do you know how much HP and torque you have? From what I have read, you are north of 500 in both categories so if you are planning on transferring all of that to the rear tires, you need to think through all of the driveline components. The Dana design is inferior to the iron differentials used from 63-79 so swapping over to one of those, properly built to handle the higher power, is one step in the process. I emphasize properly built for a reason and that doesn’t mean a run-of-the-mill rebuilding service.
With your T56, I would recommend you shoot for a ratio in the 3.70 to 4.11 range.
With your T56, I would recommend you shoot for a ratio in the 3.70 to 4.11 range.
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Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
And if you have an iron one built....let GTR1999 above (Gary) build it for you......and what else to get..I.E. Tom's axles, 1350 shafts...etc.....this is a good time to also setup the rear bearings at .001 to .003 if not done already......
Jebby
Jebby