At the risk of sounding like an idiot

[Get Down]

Can somebody clue me in. I'm looking to put 3" lowering blocks on the rear of my truck sounds easy enough. The shackles on the rear of my 49 3100 seem auful long. Should I leave them or replace them? If I replace them will that raise my rear axel also? Here is a picture to either help understand what I'm trying to say, or show my concern. I guess I'm asking if I should remove that rear shackle or just add the 3" lowering blocks and everything would be fine. If anybody care's to share pictures of their same set up I would appreciate it. Thank you

[chevyguyase]

I have a "54 3100, mine are about a third as high as yours and are precision pieces with zerk (grease) fittings. I think somebody put those on to raise the rear of the truck up. Go to American classic truck parts on line, they have pictures of what the OEM part should look like. Good people to deal with.

[Get Down]

Originally Posted by chevyguyase

I have a "54 3100, mine are about a third as high as yours and are precision pieces with zerk (grease) fittings. I think somebody put those on to raise the rear of the truck up. Go to American classic truck parts on line, they have pictures of what the OEM part should look like. Good people to deal with.

Thank you chevyguyase, I thought they were a bit long. Much appreciated it pays to ask questions on this board.

[mr48chev]

Chevyguyusa nailed it. Those were popular in the late 60's and early 70's when the jacked up in the back look was the hot lick. They usually ruined the springs rather quickly though.

It won't be right but a quick drop can come from taking them off and cutting them off just above the hole that the spring bolt is in now and flip them over and put what is now the bottom hole on the upper bolt and run the bolt that is now up in the middle though the middle hole to make a shorter shackle to temporarily get the truck down close to where you want it until you can put the right shackle kit on it. I'd go with new pins and bushings along with new shackles. If you think you want to save those long ones for your swapmeet box to see if someone wants them for that early 70's high in the back look you could wait until you get the new ones.

[OrrieG]

Make them shorter and you may not need lowering blocks, or shorter ones.

[chevyguyase]

If you want to cut them as Mr48chev says & I agree. I measured mine on the '54. The bolt in the spring and the bolt in the shackle are 3 3/4" center to center apart on my originals. Stack them together and drill them both at the same time, if this appeals to you. Don't make them to short because the spring elongates as it is compressed & also keep the center bolt.

[mr48chev]

Cutting them as I suggested will get in the ball park as far as height with original shackles. Cutting them and drilling new holes as he suggested will match the height of the new shackles but you may have to drill new holes for the bolts that hold them together.

[47 Fasttoys]

Good advice, one thing you may want to consider is the original shackles had tapered holes as the ends of the spring pins are also tapered. By just putting plates with holes on you are only getting minimal support from the shackle plates. Running long plates and straight cut holes will allow the rear end to have a lot of side to side sway when cornering. I would recommend (as others) to replace both the pins and the shackles to the original style.
Rob

[Get Down]

Originally Posted by 47 Fasttoys

Good advice, one thing you may want to consider is the original shackles had tapered holes as the ends of the spring pins are also tapered. By just putting plates with holes on you are only getting minimal support from the shackle plates. Running long plates and straight cut holes will allow the rear end to have a lot of side to side sway when cornering. I would recommend (as others) to replace both the pins and the shackles to the original style.
Rob

Yes great advise from everybody, thank you. Would anybody have a picture of their truck with the original set up they could share? I'm leaning toward replacing with the original set up.

[mr48chev]

That's the best idea, put the right shackles on it and replace the bushings and pins/bolts in the springs.

While you are waiting for the pieces you could see how low it will go by cutting off the old ones though.

[OrrieG]

Google is your friend... I would also recommend you get a factory assembly manual if you plan on doing a lot of work on your truck. Best $30 you will spend, especially if PO's have done a lot of modifications.

https://www.performanceonline.com/19...kle-Kit-Front/

[47 Fasttoys]

Glad we could help. I can get you a picture of my '46 shackles tomorrow (they are the same), now this is not free. I need your vote for Truck of the month contest for my COE. OK, so I'll get the shot either way, but I would really like your vote.
Here's the link.
Thanks,
Rob
http://67-72chevytrucks.com/vboard/s...d.php?t=680178

[Get Down]

Originally Posted by 47 Fasttoys

Glad we could help. I can get you a picture of my '46 shackles tomorrow (they are the same), now this is not free. I need your vote for Truck of the month contest for my COE. OK, so I'll get the shot either way, but I would really like your vote.
Here's the link.
Thanks,
Rob
http://67-72chevytrucks.com/vboard/s...d.php?t=680178

Listen I don't negotiate with terrorists! In all honesty they are all really nice trucks and worthy of recognition. With that said my vote was between your truck and #8 and what swayed me to your truck was well it's a bad ass truck, it has the same color and patina as mine. And it can haul every other truck there. So you earned my vote picture or not. I have to say that K50 is a pretty sweet truck! It's a tight race I did notice that. So good luck to all.

[918733]

And if you do end up using the lowering blocks they are not going to come with the right u bolts since you still have the torque tube rear end and the modern blocks might be a little bit to thick

[Get Down]

Originally Posted by 918733

And if you do end up using the lowering blocks they are not going to come with the right u bolts since you still have the torque tube rear end and the modern blocks might be a little bit to thick

The right one's would be the square one's vs. the round one's right?

[OrrieG]

Originally Posted by Get Down

And it can haul every other truck there.

Even the LaFrance Fire Truck??? Those things are heavy empty, water adds another 3500-4000 pounds.

[Get Down]

Originally Posted by OrrieG

Even the LaFrance Fire Truck??? Those things are heavy empty, water adds another 3500-4000 pounds.

That comment could be stretching it a bit, the pumper would have to be dry of course if it stood any chance.

[47 Fasttoys]

Nope, you put that fire truck on my bed and even my "E" load rated tires are gonna scream as they explode, not to mention the fact that your gonna have to tie me to a post and beat me like a dog to shut me up.

OK, this is the factory set-up for the shackles on a '46. I think it's the same for a few years after that. Notice the factory set-up has grease fittings on one side on the pins and only 1 bolt holding it all together. Seems kind of effie but my truck has well over 300K on it (daily driver from 2000 to 2015) and aside from the rebuilding all the rear spring bushings and pins back in 1999 and a little greasing they have been trouble free.
How you like those fancy mud flaps? An old door mat. Oh, and that monster to the left would be a 33 gallon fuel tank.
Rob

[Get Down]

Originally Posted by 47 Fasttoys

Nope, you put that fire truck on my bed and even my "E" load rated tires are gonna scream as they explode, not to mention the fact that your gonna have to tie me to a post and beat me like a dog to shut me up.

OK, this is the factory set-up for the shackles on a '46. I think it's the same for a few years after that. Notice the factory set-up has grease fittings on one side on the pins and only 1 bolt holding it all together. Seems kind of effie but my truck has well over 300K on it (daily driver from 2000 to 2015) and aside from the rebuilding all the rear spring bushings and pins back in 1999 and a little greasing they have been trouble free.
How you like those fancy mud flaps? An old door mat. Oh, and that monster to the left would be a 33 gallon fuel tank.
Rob

Ok thanks for the visual, I was curious how much higher the original shackle was
Compared to what's on my truck now.

Before you posted this I was looking up the weight of the C80 pumper I found a 1972 that says it's gross weight was 27500 lbs so I was stretching my comment quite a bit! It sounded good though!!

[47 Fasttoys]

Well let's see here my Cobra weighs in at 2300# so what's an extra 0 or so. With 8" air bags I could go maybe 6000# and the tires are rated at 3250 each but 27500#......maybe not. In it's original form my COE was rated at 18000# max with load. Dang I bet that in rated in gallons per mile.
And no, you can't have the visor.
Rob