4" with blocks or Springs

[dmigura]

I cant get my truck out of my head. I am always deciding on something and then changing my mind. My latest brainstorm is w/ a 4 inch lift is new rear springs necessary or will blocks be fine. I will hardly wheel my truck it will mainly stay in the garage. Maybe some mud now and then. It is a 1970 half ton and front and back suspension is in very good shape. I will need to save some money this winter b/f I do anything so got plenty of time to decide. Is there a search featur in this forum.

[a28doc]

blocks will work fine but if you want a smoother ride go with the springs the blocks make mine ride like a log wagon... the springs are more expensive tho kinda wish i hadda went that route tho
Doc

[74 shorty]

Either way will make ride different. I was looking on offroad unlimited website and they made a spring perch that actually dropped they factory spring haner on the rear side of the leaf springs. They just too factory ones off and made another set longer. Factory ride at whatever height you want.

[Mudder]

The way for a long time was blocks in the rear but lately springs seem to be the favorite. I have never had any problems with my blocks.

[special-K]

I agree with Mudder67.If your springs are good the blocks are cheapest.Then for a little under $200,there`s the shackle-flip from ORD as mentioned by 74 Shorty.They will improve your ride by changing the action of the shackle.Then for about $200,there`s the springs and you can get softer riding ones.I went this route because I had a broken leaf on each side and figured both sides were pretty fatigued.

[toddol1971]

Originally Posted by a28doc

blocks will work fine but if you want a smoother ride go with the springs the blocks make mine ride like a log wagon... the springs are more expensive tho kinda wish i hadda went that route tho
Doc

I'am not ripping you, I'am just wondering how the blocks made it ride worse. It should'nt change it at all. Same springs. Axle wrap can occur though.

[see ten]

If you run a block in the back you are only going to make the truck 4" taller than what it is now(figure 30 plus years of use and sag). With a new spring you are going to be 4" taller than the factory spec for a new spring. My K10 has springs front and rear.

[CyberRanger]

The problem w/ blocks is they increase the likelyhood of wheel hop (spring wrap) & along w/ that, u-joint failure. Blocks act like a lever & give the axle more leverage to change the springs into an "S" shape under load, particularly while starting w/ a load in the truck or on a steep incline. When the spring then "unwraps" & tries to assume its normal shape, it puts tremendous stress on the rear u-joint. This is particularly bad when using old, tired leaf springs. This is very hard on rear shocks, tryin' to suppress the spring wrap & then unload. You also greatly increase the chance of breaking parts in the rear diff during the load/unload process not to mention the greatly increased likelyhood of breaking u-bolts.

The best (not cheapest) way is to put in new springs w/ the 4" arch built into them. You greatly minimize spring-wrap & your ride will improve as well as traction.

No blocks for me!

[special-K]

Makes you wonder how a truck manufacturer could get away with it for all those years.There`s alot of negative hype over blocks.That`s all it is.As long as you drive the truck like you respect it,you will rarely experience wheel hop.Not enough to harm anything.

[Dean]

I've done it both ways on several trucks and here are my observations. I've never been able to haul as much weight with the new springs in the back. I guess it might have to do with the springs being soft ride and etc. The 87 K30 that I'm starting on now I'm going back to the 4" blocks in the back so I can keep the original springs. For normal use I doubt you would ever see what I have observed.

[1967k30]

Build your own shackle flip.Get a pair of spring hangers off the front of the rear spring and install them in place of the original rear ones.I used ones from an 80' 1ton dually and they were perfect.I tryed some form a 75' 3/4ton and they weren't the right spacing. You can gain up to 6" with them depending on which hole you use to mount them.

[CyberRanger]

Originally Posted by Dean

I've done it both ways on several trucks and here are my observations. I've never been able to haul as much weight with the new springs in the back. I guess it might have to do with the springs being soft ride and etc. The 87 K30 that I'm starting on now I'm going back to the 4" blocks in the back so I can keep the original springs. For normal use I doubt you would ever see what I have observed.

Aftermarket lift springs were never designed to carry a load. They are designed for four wheelin'. I have 'em on my truck. I put some custom airbags to I can haul when necessary & still four wheel it. The regular overload airbag kits won't work w/ any lift. Been there, done that.

I'll try to get a photo of my air bags & post it. They're air bags used on 40' flat bed trailers & match the travel of my installed leaf springs.

I know for a fact that lift blocks, factory or not, were never a good idea. I've fixed too many trucks that had 'em. I've seen bent leaf springs, wrecked u-joints, bent shocks, trashed diffs, etc., etc.

OEM lift blocks usually worked b/c the engine was stock, the gearing was stock & the tire size was stock. Anything beyond stock would stress the rear axle/spring/diff/u-joints beyond the designed specs.

[74 shorty]

Here is my opinion. If blocks were good enuough to be used on leaf spring vehicles, Then it would have been no problem to use them on the front to. But if you do that I will pray for youre sorry soul and whomever is with you when it decides to give out. I am not saying that blocks on the rear will give out. But think of it this way. Think of your axle as a nut. Now when you come across a tight nut that is to tight for a ratchet, what do you do, get a longer ratchet or a breaker bar. Now think of the block as a wrench. The longer it is, the more rotating force it puts on your axle. Now as for factory, most are just two inch lifts and they are with factory tires which do not get as much traction as oversize tires do. Also when you start lifting the truck, chances are the performance of engine goes up. Both are not factory designed. If it was me, if it is going to be street driven, light loads and not to much hotrodding blocks are fine and please do not stack them. As for my driving, offroading, loaded, and otherwise used as a truck, shackle flip is the best imo. You use factory springs (new or original) so therefore everything remains same. Load capacity is factory, ride is same with exception of tires. Sorry for the novel!!!

[special-K]

Oh boy,here we go.I`ve run lift blocks on trucks since 1977.Never had any problems.I guess I got some wheel hop on the pavement w/14.50x37"tires when I dumped the clutch on pavement.What I mean is just lifting the foot off the clutch pedal with no gradual engagemant.If I revved them and "popped" the clutch,It just spun the wheels.It`s true,this is not good for the u-joints(or the rest of the drivetrain).The only thing I even broke was the intermediate shaft on a divorced set-up.This would not have been any different with any spring/block set-up.This occured after a day of cruising through town,buzzed,in low tranfer and bucking the truck(you know:erk-erk...erk-erk)spinning the tires,then letting off making them skirch,alot.Then,ending the day in sediment ponds,churning around in that slop until it wouldn`t move,then backing up and hitting what stopped it and grinding into it till it would go through.Then climbing out,only to turn around and take it down into the muck again.I was letting my friend do this,too.If he got it stuck too bad,I`d take over and get it out.Finally,one time climbing out,"Wham!!Thump Thump Thump".The drive shaft wrenched itself into two pieces(2" of tube).I had topull the shaft,get it fixed,and re-install it in the sediment to get my truck out.This is only one story.Anyway,I don`t think the blocks were ever a problem.And`if someone ever wheels a truck harder than this,there ain`t nothin`that`s gonna save it.

[toddol1971]

i've used 4" blocks for years. If theres nothing wrong with your springs, i'd use a block. Unless you are into alot of off roading. Then i'd use springs. Eaton detroit springs can build you a stock weight spring with a 3" lift or 2" lift. Then you could use a zero rate block. They wont make a higher lift than 3" though. Thats a great option if you want to tow & don't want to use air bags. Someone mentioned not being able to use air bags with a lift. Thats wrong. All you need is a spacer like a piece of pipe the same size as the mounting flange. Also i've been seeing lately that some manufacturers of air springs are making them for different lift sizes now. You knew it was a matter of time with all the 3/4 & 1 tons running lift kits.

[CyberRanger]

Originally Posted by toddol1971

... Someone mentioned not being able to use air bags with a lift. Thats wrong. All you need is a spacer like a piece of pipe the same size as the mounting flange. Also i've been seeing lately that some manufacturers of air springs are making them for different lift sizes now. You knew it was a matter of time with all the 3/4 & 1 tons running lift kits.

OK, let me clarify myself on the airbags. You can use 'em, but you'll lose all the extra travel you get w/ the lift, depending on the lift. Lifts 20 yrs ago simply made the truck ride higher & give you no more travel than stock, which isn't much. Kinda self-defeating off-road. Newer lifts give you the lift AND give you more wheel travel. The add on air bags you can get now cause you to lose that extra wheel travel, negating much of the effect of the lift. If the airbag they give you in a kit is only 4" or 6" tall, it isn't going to give you much travel. My springs currently allow me about 5" of up-travel & about 8" of down-travel. In order to keep that I did the custom airbags. Every kit I looked at limited me to about 2" of up-travel & maybe 3" of down-travel unless I disconnected 'em when four wheelin' which is a huge hassle.