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Lowering a leaf spring car

12K views 41 replies 21 participants last post by  NOBOTL 
#1 ·
I have a 66 chevyII with leafs. The leafs are in the stock holes (moved inword)front with sliders on the rear. Could putting a 1" block to lower the rear of the car make it hook better? I am running on 275's and can only leave at 5000. When I try to leave on the convertor (6800rpm's) I blow the tires off. Shocks are afco doubles an front and back.
 
#6 ·
Is it okay? Can you make it work...if we add a 1 inch or 2 inch lowering block under the rear end to lower car more?
 
#16 ·
I talked to Calvert about lowering blocks, they said to use steel blocks. 1" block nothing any bigger and can hold 1200hp. I really don't know if I should do this. My motor has 800hp. Firetruck1: what kind of HP are the cars you are talking about have? I am in the process of building a 950hp sb to put in this car.
 
#17 ·
Firetruck, George,
I have 1in lowering blocks on mine that I have machined out of steel. They have large slots I machined in them to lighten them up some. I also have larger U bolts I had made at a Diesel truck shop. I'm making in the 1500hp range and have no issue.

Slowcar,
Leaf spring cars dont like soft shock settings very well. You will tend to unload the tires right after the tire hits. I run mine more to the tighter settings on compression and extension.
Plant the tire. The looser the extension, the harder it will hit the tire on initial hit. But will also unload the tire upon seperation if too loose.
Let the weight of the ass drop, hold the weight down on the tire with tighter compression settings
Once the car moves, let the springs seperate slowely as not to unload the tire (tighter extend)

This is what works for me as a starting point. I run 4.90's through the 1/8 with 60's in the lower 1.20's

Hope this helps.
 
#35 ·
Firetruck, George,
I have 1in lowering blocks on mine that I have machined out of steel. They have large slots I machined in them to lighten them up some. I also have larger U bolts I had made at a Diesel truck shop. I'm making in the 1500hp range and have no issue.

Slowcar,
Leaf spring cars dont like soft shock settings very well. You will tend to unload the tires right after the tire hits. I run mine more to the tighter settings on compression and extension.
Plant the tire. The looser the extension, the harder it will hit the tire on initial hit. But will also unload the tire upon seperation if too loose.
Let the weight of the ass drop, hold the weight down on the tire with tighter compression settings
Once the car moves, let the springs seperate slowely as not to unload the tire (tighter extend)

This is what works for me as a starting point. I run 4.90's through the 1/8 with 60's in the lower 1.20's

Hope this helps.
Good info!!Thx.
 
#32 ·
I've never really had good shocks when I use to run them staggard, so I didnt have any data to go by back in the day. My shocks are actually still in the stock location at the trunk pan, so they are angled. Most people run them straight up and down, but I have Afco double adjustables set up with higher valving
 
#23 ·
Lowering it will make it harder to hook, lowering a leaf car "always" takes away its potential for seperation. Getting controlled seperation is what you WANT with a radial.

Right now you have a seperation control problem, in the front and the rear, you need to work on your shocks.

You need to tighten extension in the front and rear, it wont do the cool wheelies but it will work much better.

Everytime you add power, the tighter the front extension will need to be. If they are stock valving afco da's on the font, do not be afraid to try full stiff on front extension. Full stiff on stock afco's is really not that tight, most fast radial cars end up with a much tighter than stock valving package. (3-5x tighter)

Once you find a good place in the rear, you wont need to play with it as much, unless you make LARGE swings in power applied

This is my method in action on a bad track (146*), slower 60' (1.25), everything is still slow to move
http://www.youtube.com/watch?v=BaM5-PijXMc


first attempt at more power on a good track (1.17 60'), still needs more power and more shock control:p
http://www.youtube.com/watch?v=-z7a0B2kaq8
 
#20 ·
Nuclear, you obviously have done it right. You went with a reasonable block (1 inch) and larger bolts from a shop who deals with heavy torque monsters. My comments were made towards the people going with those cheap shit cast aluminum ones form the parts store and then wondering why they have problems. I will say you are the exception to the rule with the lowering blocks in that you have a more well thought out set up then 99.9% who go this route.
 
#22 ·
Yep and this one of the reason why they are no good on high HP cars.
 
#24 ·
66 ac cobra, thanks for the input. I wish I could test this weekend but its frozen where I am! It's going to be two mouths before I will see the track. I will change the shock setting before I lower the car. Thanks and any more input would be greatful.
 
#25 ·
Slowcar, I have seen cars wit as low as a couple hundred horse have issues and have see only a couple 1000 plus make them work. This is not to say you cant do it or that you will definitely have a issue, you just have to think carefully and use stout parts. Your on the right track with the information you will find here.
 
#26 ·
Gonna be a couple cars from here testing to see how low you can get with a leaf car. I'm lowering mine about two inches all the way around, but have a buddy that is lowering his leaf X275 Camaro like 5 inches! It's gonna be on the ground.

Of course, he designs suspension components for Smith Racecraft.
 
#28 ·
The car in my avatar is a leaf spring car. 5 leafs each side. I lowered it by building adjustable front mounts. After doing it I could have gotten it an inch lower with a different design front mount. I used a 1" steel block and sliders. I raised the trunk floor in the car 1/2" to allow my slider mounts to stay under the floor.
 
#33 ·
#34 ·
Banana talk to me man..my cars a Drag car built by the owner of Somerset Toyota in Kentucky..the dam thing had small shackles in the FRONT of the Leafs n Sliders in the rear. ? Whut do you think..maybe the springs were dyin or a different way to LOOSEN IT UP ? Blew my mind but I seen him launch it and it was nutts !
 
#36 ·
Banana talk to me man..my cars a Drag car built by the owner of Somerset Toyota in Kentucky..the dam thing had small shackles in the FRONT of the Leafs n Sliders in the rear. ? Whut do you think..maybe the springs were dyin or a different way to LOOSEN IT UP ? Blew my mind but I seen him launch it and it was nutts !
Shackles up front and sliders in the rear?? WOW.. Seems like that would be a LOT of back and forth movement with the springs. I have never heard or seen anything like that. Do you have any pics of the front?
I know some of the old super stockers with leaf springs and ladder bars use floaters on the springs to set the rear on to prevent binding. But I dont know if this would have the same effect? It's possible though. If the car has/had ladder bars to the rear housing, then the springs were just there to support weight. There would be no back and forth movement due to ladder bars, so the springs wouldnt even , nor the rear housing, other than compression movement. So, your leafs are just there to support the weight of the car basically. The shackle on the front sounds like a "poor mans" floater.. IDK.....

My question to you is, does this car have Ladder bars? If so, your leafs have no function but to hold the weight of the car (like a coil over spring)
 
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