Site Navigation

Recent Posts
My 1997 Express
by Rusty_Pancelode. July 24th 2017 5:56 pm
Photobucket .... all comments here
by tuner4life. July 24th 2017 9:21 am
Ariel's 1989 Dodge B350
by lukester. July 23rd 2017 9:40 pm
1982 B150 Prospector
by blevins2005. July 23rd 2017 5:26 pm
Vanning shops
by CustomD. July 23rd 2017 9:28 am
Sec Econoline from Germany
by Hendrik84. July 23rd 2017 4:50 am
'78 Dodge Street Van - Twin Cities, MN
by lukester. July 22nd 2017 8:15 am
interior panel installation, conquering the curves
by VCVCSmiley. July 21st 2017 10:49 pm
Featured Links
Vanning.Com is a an authorized Amsoil Dealer

Previous Thread
Next Thread
Print Thread
Rate This Thread
#725191 - June 30th 2017 9:49 am 1985 Chevy with 3:42 (GU6) rear axle, want to change to 4:10  
Joined: Sep 2013
Posts: 510
tuner4life Offline
tuner4life  Offline

Joined: Sep 2013
Posts: 510
I do a bit of towing with my 1985 G20, it's no secret that the 305 struggles with pulling anything over the van's own weight around. My original plan was to use the 305 until it showed signs of dying then swap to an LS, but after nearly 3 years of use, mostly towing a trailer with a car on it, the engine still seems to be in good shape. I figure I might as well try to make it's life a bit easier. Plus it will be nice to have that already taken care of when I do swap to LS power down the road.

The van currently has a 3:42 (RPO code GU6) rear gear and I want to swap it to a 4:10 with posi. I've done a bit of research, but I am used to the imports with independent rear suspensions and the differentials are much simpler to set up (less of the marking/painting/crush spacers/etc). The old GM rear ends seem a bit more complicated to set up plus I have no clue what the best parts are to buy.

So, my questions:

-What should I buy to convert my rear end to 4:10 with and without Posi? Trying to see what all the options are, but what brands should I look at vs avoid, etc.. What do you recommend?
-Also, what is a link to a good guide for setting up a rear gear like this one? I've read a few different "instructionals", but looking for something more technical with actual torque specs and such.

Thanks in advance!

Last edited by tuner4life; June 30th 2017 9:50 am.

[Linked Image]
1985 Chevy G20 305ci/4spd Manual
#725380 - July 05th 2017 8:03 pm Re: 1985 Chevy with 3:42 (GU6) rear axle, want to change to 4:10 [Re: tuner4life]  
Joined: Mar 2013
Posts: 94
DC79 Offline
DC79  Offline

Joined: Mar 2013
Posts: 94
Lake Isabella Califronia
I have a 84 G30, 350 with a 700r4 3.73 with 9.50R16.5. Ive pulled a u-haul auto trailer, the one with all 4 wheels of the car off the ground. I ve had a 2001 corolla and a 1997 Jimmy (small) on it. its ok on flats at 65mph, but any slight hill and its 3rd gear. up a hill its 2nd and under 55mph. I have thorley try-y's for it but have yet to put them on.
I think saving for the LS or for me a 383HT is the way to go.

1984 G30 Chevy

Moderated by  Astro 


Upcoming Events
Fall Fest 3
Instagram Feed
Who's Online Now
0 registered members (), 1 guest and 5 spiders.
Key: Admin, Global Mod, Mod
Newest Members
carnut2, Ariel1234, Vinnie, cuervo8, Keightley
9808 Registered Users
Top Posters(30 Days)
Dyno_Dave 108
lukester 105
frscke1 64
Wedgy 27
Reed 24
Matman 22
Forum Statistics
Most Online177
May 8th, 2013
Tinfoil Security

Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.043s Queries: 15 (0.010s) Memory: 5.7263 MB (Peak: 5.9343 MB) Zlib enabled. Server Time: 2017-07-24 22:31:44 UTC