Changing gear ratio
Thread Starter
Pro
Joined: Nov 2004
Posts: 667
Likes: 87
From: Bismarck IL.
Changing gear ratio
I bought a complete rear end out of a 79 with a 3:55 gear.I plan on putting it in my 73.My 73 has a LS1 with a 4l60 transmisson and a 3;08 rear gear.What will be the difference i n rpm's ? The side yokes on the 79 rear end has U bolts and the 73 the caps.Which is the strongest? Thanks Charlie
Drifting
Joined: Sep 2006
Posts: 1,259
Likes: 2
From: MS
The caps are the strongest.
For the RPMS, use this: (transfer case ratio enter 1)
http://www.4lo.com/calc/gearratio.htm
The 4L60 has a .70 4th gear and assuming 27 inch tires we have:
-------70 mph------80mph
3.08 - 1878 rpm - 2146 rpm
3.55 - 2165 rpm - 2474 rpm
For the RPMS, use this: (transfer case ratio enter 1)
http://www.4lo.com/calc/gearratio.htm
The 4L60 has a .70 4th gear and assuming 27 inch tires we have:
-------70 mph------80mph
3.08 - 1878 rpm - 2146 rpm
3.55 - 2165 rpm - 2474 rpm
Tech Contributor
Joined: Aug 1999
Posts: 15,154
Likes: 3,959
From: Connecticut, USA
Cap on the yokes are the "HD" type. They're the same yoke only use caps instead of U-bolts. The 78-79 diffs were not too good. I strongly suggest you look it over good before bolting it in place. They had soft yokes, poor RG bolts, & poor clutches to name a couple of things to check. The 73 diff isn't really much different, other then the yokes, RG bolts were better they used the same crappy clutches. Both can be made 1000 % better if you take the time to build them.
Good luck
Good luck
