what do I need in your opinion

[possum]

I have a 1978 Chevy K5 Blazer (what else

), 350 v8, th350, np203, 4" RC lift, 33x12.50x15 BFG MT, and I believe 3.08 1/2 ton axles (or is it axel). I am wanting lower gears and 35" tires. That's probably the largest I'll get. Well, maybe

. Eventually I'll get the doubler but that'll be awhile from now. I drive maybe 20 miles a week. I work at home and my driving is pretty much limited to taking the kids to school and babysitter's. I want the truck built for 4wheelin. What gears should I get? I'm thinking 4.56, others say 4.11. What axles can I get these from and from under what vehicles can I get the axels? I need all sorts of opinions so I can make an educated decision. My budget allows this to be done only once. Also, what changes will I have to make to switch the axles if need be? Thank you.
<a target="_blank" href=http://community.webshots.com/user/possum1970>http://community.webshots.com/user/possum1970</a>

 

[possum]

hmmm and I thought opinions ran rampant here and were free.

<a target="_blank" href=http://community.webshots.com/user/possum1970>78 K5</a>
we're not always who we are

 

[Dieselmh]

I'll give you my two cents, although I'm sure I'll get corrected later by someone else. I also run a 350/th350, but am going to 38's. I have been told to run 4.56s, so 4.11s should be fine for 35s, but 4.56 may be better for 4 wheelin' since you don't drive it much. I am also doing the 1 ton swap, but reccommend sticking with your stock stuff until/if it breaks. I'm swapping now because I'm gonna do the engine/tranny/axles/lift/brakes/etc... all at once, and don't want to have to go back and fix stuff later because I got cheap. 1 tons aren't cheap, and they're getting harder to find, so I chose to buy them now. From what I hear, the 70's and up 1 ton stuff will fit, but a dually front requires some mods. I know this doesn't really answer your questions, but maybe it will get others to thinking.

Diesel

Shouldn't it be called uncommon sense?

 

[possum]

I could say something really outrageous and then... everyone will come out with their opinions

. I guess people like correcting.

<a target="_blank" href=http://community.webshots.com/user/possum1970>78 K5</a>
we're not always who we are

 

[ChadH82]

If you ever get on the highway 4.11 gears would probably be the best for the 350 tranny. If you drive in town all the time you can use 4.56 but it will reduce your mileage on the highway and you'll be turning a lot of RPM's since you don't have OD. I'll just get to the point and say 4.11's will be okay offroad and better on the road. 4.56 will be good offroad and marginal on the road.

Chad
'73 Blazer,383,400,Atlas II,D60/14 Bolt,traclok/detroit,39.5 Swamps <a target="_blank" href=http://members.aol.com/fileholder2meg/projblazer.html>Clicky</a>

 

[k5king]

well,,if you are planning on taking even a few " short" trip's in this or hitting the highway,,go with the 4.11's,,if you don't plan on running the pavement that much,,go with the 4.56's,,they will be much better for offroading. i am going to be running 38's when i get mine done(i hope) and im going with 4.56's only for the fact i would be driving it on the road and want to try to have decent mileage.if not i'd be in the 4.88's or higher.
if you want 3/4 and one ton stuff just go check out as many local yards as you can for heavy duty rig's,,but DON'T tell them what your looking for,,just say you wanna go look at some rears for half ton stuff and if you find a set of 3/4 or one ton's,,,ACT STUPID !! lol
some guy's will jack the price up if they know you want them for other than stock applications,,or just plain WANT them !
you can print out the pic's from the " technical " section(i think)
and take them along to look at the houseing's if you happen to find a set.
i'm not sure but i think all the D 60's and corp. 14's are the same in any make of vehicle,,just spring perches and what not are different,,,,talk to " wayne " about that,,he deal's with rebuilt HD axles of the like. might be able to tell you somehting more.

<font color=purple>ANYBODY LOSE THEIR JEEP????????

I JUST FOUND ONE UNDER MY BLAZER!!!!

</font color=green>

 

[Rebel88]

heres my two cents as well...youll go with 35s now and then in about a few months time youll want 38s...so just to be prepared for that change go with 4.56 gears(might want to think about a locker if youre doing extreme offroading)...i am in the process of the one ton swap and i am deciding to go with 4.88s because of 39.5s and a 700r4 tranny...you dont want to go with 4.11s then step up to a set of 38s and suffer from a lack of power...do it right the first time

im done now

Later

Have you driven OVER a Ford lately?

 

[BLUESMAN]

I have your K/5!!! Same year,and powertrain and had the suck a## 3.08 gears w/ 33" tires.I was going to limit myself to 35" tires(I even have them),but a deal came along that included 3/4 ton diffs w/ 4.56 gears.....now I'm running 38" tires.Here's my suggestion......Try to carefully plan and know what exactly you want the truck to do and what size tires you're going to run.Rather than regear your present differentials( going to cost you around $600),I would look for diffs with the gears you need.If you going to run 35" tires the 12 bolt rears will work nicely,anything larger and you really are going to want a 3/4 ton diff.The nice thing about 3/4 ton diffs are that 4.10 gears are not uncommon(3.73,4.10 and 4.56 were all available).I would agree 3.73 for 33" tires,4.10's for 35's and 4.56 for 38's.But this is for your current trans(TH350), if you go with a TH700 trans then it's another story.The TH700 has a lower 1st gear and overdrive which means you would want to go to a lower gear set than with a 3 speed trans.DECIDE what trans,gears, tires and how you are going to drive your K/5 and maybe you can build it once.Good luck!!!

 

[possum]

I don't mind going to 3/4 or 1 ton axels. I keep hearing 14 bolts are tough and I like the tough idea. Pulling my 4 wheeling "partners" out of the mud can really put a strain on things. Does anyone know where I can find the codes for determining the gear ratio by the numbers inside the differential? Isn't there a number or something stamped inside the diff? And is there a website or something illustrating the different locker types or limited slip and all those?
I'm new to all this and really have never seen these inside the axel.

<a target="_blank" href=http://community.webshots.com/user/possum1970>78 K5</a>
we're not always who we are

 

[wayne]

IMHO I will say go with 4:11's. Reason being is if you plan to stay on 35's and run the doubler you will be fine and still be able to run 70mph all day long. Cheapest and easiest way to go is just swap axles.

See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
<font color=blue>Wayne<font color=blue>
<font color=blue>Happy Trails<font color=blue>