Knuckle & lift size question!
 

I own a 1970 chevy 4x4 that is completely stock. I have been wanting to put a lift, tires & rims on it since I bought the truck last year. Here are my questions. Keep in mind that I wont do much else to the truck for several more years.

(1) Should I keep the stock lift and slap some 31x10.50x15's on the original rims and be content with that for a couple of years?

(2) Should I buy a 4" superlift HD kit (No-blocks) some 33x12.50x15s and a new set of rims?

(3) Should I buy a 6" superlift HD kit (No-blocks) with 35x12.50x15s and new rims?

The way I figure it, the 6" lift kit isnt much more than the 4" lift kit, the tires arent much more and the rims would cost the same. I plan on using a steering stabilizer with whatever size lift I go with.

I know I need a steering arm, what else would I need to do if I went with a 6" lift rather than the 4" lift? I believe I have to get a new driveshaft made or something with a 6" lift, correct?

Does anyone have any pro's or con's for going one way or the other?

My last question is all the lift kits say that I require an (OPEN KNUCKLE) what exactly is this? Is the difference between an open or closed knuckle the boot or housing? I have attached a picture of my truck, maybe someone can tell me as well as point out to me what an open knuckle is? Thanks again.

That is an open knuckle front axle. The closed knuckle type have a ball that is sealed around the axle-joint. You cannot see the axle in the closed knuckle units.

Generally lift works the same as lowering....go with the greater amount the first time. Most people are disappointed by the lesser amount and wish they had gone more. Just be aware of the change you are making to your effective gear ratio with the taller tires.

Most recommend using an off-set pitman arm for any lift above 4". You probably won't need a new driveshaft for 6" especially if it is a LWB truck.

Here's a pic of my closed knuckle on my '69...

even if you do run four id run some 35 inch tires , they fill out the wheel wells and look way better imo

I have some pics in the link in my signature of my two. On the 71 I wish I had went with 6" of lift.

71 with 4 and 33`s
 

Here is a picture of my 1971 with 4 in and 33 in tires. I'm happy with it.I guess it really depends on you.....John

Steering stabilizers are something of a marketing scam. Usually, steering stabilizers are only needed when there is something wrong with the steering, suspension, or tires & rims. Bump steer is the most frequent fault that motivates some 4x4 owners to install a stabilizer. The dropped pitman arm Longhair mentioned would probably eliminate any bump steer encountered without one on 67-72 GM trucks lifted 6" or less. Large radial tires rarely need one, but large, agressive bias tires might if they come from the mold out of round, uneven weight, etc. So, if after lifting your truck you think you need a stabilizer, look into whether the set up is right first.:)

now that aint fair john , you could knock the tires clear off that truck and set it on the hubs and its still gonna be absolutley gorgeous , wow , you cannot beat an orange short fleet 4x4 they will always hold a special place to me , wow , absolutley gorgeous

Ok thanks for the info everyone. So I have seen a couple pics of 67-72 trucks with 4" lifts, does anyone have some of 6" lifts?

Sooner, i think everyone here has forgot one very important element of building a good usable 4x4 truck.

What gear ratio do you have? if you have anything higher than a 3.73, do not lift it or install bigger tires. doing so will turn it into a gutless pig, and it will drink gas like no other. you'll hate driving it because of this.

Ok thanks for the tip. Would anyone know exactly what a stock 70 4x4 1/2ton pickup came with in 1970? This has a stock 4 speed manual tranny will that make a difference in its performance? I think when I measured the tires that are on there now, they were around 29". This truck wont ever see the mud. It will be a weekend driver and occasional boat or merchandise hauler from town. I want it to handle and perform well but do not intend to go off-roading in it.

regarding your use of it, too tall a gear will make it undrivable anywhere, not just offroad.

my vote would be to do option #1, and then save up for everything later.

Here is a pic of my '70 before I tore it apart. Here it has a 6" lift and 35's.

Gear Ratios. Check if you still have the Service Parts Identification Decal in the glove box for RPO Codes. H01 = 3.07, H05 = 3.73, H04 = 4.11 There is also a axle code number stamped on the bottom of the left or right axle tube beside the carrier housing on the rear diff. Eg. TDG = 3.07, TDF = 3.73, TDJ = 4.11 there are more codes. The only way to tell for sure is to take the diff cover off and check the codes on the front of the ring gear and divide them. Eg. 41-11 = 3.73

Well I checked and either its not there or I am crazy! I have my SPI, infact I have provided a picture of it below in case I am not seeing where it tells me what my rear diff is, someone can point it out?

I also climbed up the rearend and looked for about 10 mins for the stamped axle code. The only numbers I saw were on the drivers side of the housing and went like this:

1 2 3

6 7 8

Any other ideas? If I take the back plate of the housing do I need a new gasket of just a silicone bead? I.E. which would be the correct method.

No diff code, might mean 3.08's. Before you pull the cover, check your front cover and see if it has a metal tag attached to one of the cover bolts, it will have the ratio on it. A gasket or silicone will work to seal the cover.

Re: Knuckle & lift size question!
 

I have a '70 blazer I'm looking at putting a 6" or 8" lift in it. It has closed knuckle steering. What do I need to do for the conversion to open knuckle?

Re: Knuckle & lift size question!
 

you would have to change the axle to a open knuckle axle from a 71 up 4x4.

if it was me i would go big i have 6 now and wish it was 8. for steering I would not wast money on a drop pitman arm or a rased steering arm if your going to go 6in or more I would just put that money twards going to crossover steering with the cost of the arm and the steering stabilizer you would almost be at the same price any way and it still would not be as good of steering set up. here is a pic of my old blazer with 6in lift and 3in body lift and 36in tires

Re: Knuckle & lift size question!
 

i vote for #1 i'm not one for big tires and a lifted truck for highway use but like the way they drive and perform at stock hight with 31s way easier to load if you use it as a truck too

Re: Knuckle & lift size question!
 

A 3 year old post...to the day. I am always amazed at how new guys surf through the old stuff. It's cool to actually search....

Oh....I did mention gear ratio, so it wasn't everyone ;)


BTW, welcome to vanislejimmy

Re: Knuckle & lift size question!
 

I ddint even notice that. I never pay atention to the dates.

Re: Knuckle & lift size question!
 

I don't always notice the dates either, but I remember that post. It is far easier to notice it when you have posted to the thread when it was new.

Re: Knuckle & lift size question!
 

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Last Activity: 08-16-2006 04:04 AM