1971 3/4 swap to 1/2 ton

[Charlesdur]

Hello everyone,

I have been searching like mad and need some help. I just snatched a 1971 fleetside with a screamin 454 for $1000.00 (family deal). It is a 3/4 ton with rear leaf springs and drum brakes. Front has coils and disk brakes. I want to convert it over to 1/2 ton so I can have 5 lugs and do a 4/6 drop on it. I will list what I have currently been told and have been searching threads, but starting to think that I might be out of my mind. I could buy a 1/2 ton and move my engine over, but it was the grandpas truck and cant do that.

#1 (REAR) need to swap out the rear end and find a 9.5” 14 bolt semi floating rear differential so that I dont have to get a new drive shaft. These come in 5 and 6 lug, but the 5 lug is hard to find and expensive.
Any direct bolt on advice woule be GREEEEEAAAAATTTT...

#2 (FRONT) I can buy a complete kit from ECE or LMC truck and swap it all over. My question is that since these kits are made for 1/2 ton trucks and I want mine as a 1/2 ton will it work?

#3 Find a 1971 or 1972 with all of its suspension and transfer over

Added some pictures of my 390 and bagged 66 tbird and the 454 in my new 71 3/4 ton.

Thanks

[LockDoc]

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First off welcome to the board from the "Corn State".

I am going to be doing the same thing shortly. Luckily I have a '69 I can take all of the 1/2 ton stuff off of and use on the '67 3/4 ton. It won't give me 5 bolt but I'm not worried about that right now. I can't advise on the kits. If you could find a later donor truck and just swap the components over I think that would be easiest....

LockDoc

[Charlesdur]

Leon,

That does help to know that you are switching them over. It sounds like they are a direct bolt on so that gives me a great start. I have owned 6 tbirds, so I can do that blind folded, but since I had to learn by trial and error all of those years I wanted to turn to the Chevy pros before I really started to dig into my 71. I always wanted a truck, always wanted a chevy and damn the 454 is nice. Now I want to make it the way I want it with other truck owners advice.

Thank you
Charles

[LockDoc]

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If yours has the leaf springs you would have to find a 1/2 ton with rear leaf springs for it to be a direct bolt in. Most of the GMC 1/2 tons have leafs on the rear and most of the Chevy's have a coil spring rear. The GMC would be a direct bolt in also.

LockDoc

[Charlesdur]

I found a posi 12 bolt out of a 71 C10 for $400 with leaf springs. Is that a good deal?

[LockDoc]

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I guess that's a good deal but I'm not up on my posi prices.... For me it would depend on the ratio. I have a 454/TH400 combo in the white truck and it had a 3.73 open rear in it. It seemed to work the motor a little hard so I changed it to a 3.07 open and it made the truck a lot more drivable and it still has plenty of low end torque.

There is a code number stamped on the rear end housing (see pictures). Look the first two or three letters up (earlier years have two letters and later ones have three) here, in the axle section:

http://www.americanclassic.com/paint.htm

That will tell you the ratio.

LockDoc

[nightmare]

it is still possible to do the 4/6 drop with it being 3/4 ton. why are you looking for the 5 lugs? is it for the rim choices, or just because you want a 1/2 ton? you've already got disc brakes, so you don't need that. there are plenty of rim choices for the 8 lug pattern. just a thought

[Charlesdur]

I want to go with 5 lug for the rim choice. I have looked around at 8 lugs, but I cant find the style that I want. I just found a C10 for $500.00 so I guess I pay $1000.00 for my truck and at least $4,000.00 to get it close to what I want... of course not including paint and body.

[Charlesdur]

Originally Posted by nightmare

it is still possible to do the 4/6 drop with it being 3/4 ton. why are you looking for the 5 lugs? is it for the rim choices, or just because you want a 1/2 ton? you've already got disc brakes, so you don't need that. there are plenty of rim choices for the 8 lug pattern. just a thought

Nightmare,

Can you point in the direction to find the 4/6 drop for my 3/4 ton. I actually found some really cool wheels by MKW that I will fit the 8 lug.

Thank you,
Charles

[nightmare]

Theoretically, you could take stock ½ ton front springs and use those. That should drop the truck in the front about 2” or so, maybe 2 ½ “. To get lower, just get a set of 1” drop springs for the ½ ton. Those generally run about $100 for the pair, maybe less.

I say theoretically since adding ¾ ton springs to a ½ ton nets you around 2” of lift, the opposite should hold true too. Someone else may have more experience with this, and could give better advice.

For the rear, since you have leafs, you could get an axle flip kit, de-arc the springs, get a shackle kit, or remove a leaf or two from the spring pack. If I remember correctly, ½ ton trucks have 4 leafs in the pack, whereas ¾ tons have 6. I would recommend the axle flip kit, since that should get you the most drop for your buck. My guess would be around 6” – 8”, for around $250 or so. But removing a leaf and shackle kit should get you around the same drop for less.

Now, as far as where to get these things, some of the board vendors may have them. You could also try your local speed shop, or searching online.

[ratpackv8sonly]

Just to make life easier for you on the rear end you can put a cross joint (u-joint) at the axle so it wont matter what 12 bolt you put in it. Being leaf spring in the rear makes it very easy to install almost any rear axle. I would find a ford 9 inch out of a 1978 Mark 5. It has rear disk and is Chevy 5x5 lug pattern. For the front just get the parts from a 1973 and up chevy 1/2 ton. Just what ever spindels you use you need to take the complete steering linkage with it. Its easy to do this swap as I have done it many times for my friends and family. I think there is over 20 of these trucks between us.

[lowriden58]

this may sound dumb to so.. but is much cheaper and easier IMO. why not just get some custom axles made from Moser? they will have the 5lug pattern you want and wont have to swap the whole assemble? its like 300bucks for the axles. and then you can just do a spindle swap up front unless im missing something on the 3/4ton ?? grab some lowering leafs for a 1/2 ton and put them in there

am i missing something?

[Charlesdur]

Any advice works for me and that is probably the best idea yet. I would love to keep the strength of the 14 bolt rear end and simply do an axle swap. I will call Mosher today! Thanks lowriden58 I will post what they are going to charge me and if they can do it.

[Charlesdur]

Nightmare,

Thank you very much for the info. Now it sounds like I have some actual options and can get the look that I am looking for.

Whatever I end up doing I will post the pics.

I took my truck for it's first 35 mile commute yesterday. The alt bolt broke off in the block, the bolt then moved up and punched a hole in my radiator, my battery took a dump and I am thinking that I will need to replace the starter. Today the radiator is fixed, new battery in and I bought a tap out kit to remove the alt bolt from the block. Now searching for a mini starter on summit... The best part is that I had the truck in the garage next to my tbird last night and I had a Tim Taylor moment... thinking "now, this is a mans garage"

[Charlesdur]

ratpackv8sonly,

Thank you for your help, now I have aobut 5 options to run with.

[Charlesdur]

I contacted Moser and they said that they can't make a 5 lug axle for my housing. Doing the following for a total of $867.00 so far. Good thing my wife doesn't know about this forum!

Picking up a complete 12 bolt posi rear end, leaf springs, drive shaft, front spindles, brakes and calipers out of a donor 1971 C10.
$500.00

Front: Ordered 2 inch drop springs and shocks from LMC truck
$240.00

Rear: Ordered a rear flip kit built by DJM Suspension from Godfather customs.
$127.00

Link to DJM
http://www.djmsuspension.com/Product...63C10Parts.htm

Link to Godfather customs
http://www.godfathercustoms.com/

[Sinister]

GMC Paul's has lowering springs for 3/4 tons, but it looks like your already set up. Good luck...

[Steelawork'n]

Don't forget to show pics of the building process. Can't wait to see them

[67chevemall]

While your at it put air bags on the truck and rid the leaf spring
suicide doors will set you up big.

New axles or 8 lug wheels/tires

$0.02

[Charlesdur]

So in my hunt to figure out if 1/2 front springs would work in my 3/4 I decided to see what springs I would have to order if I needed them new. I went to LMC truck and the 1/2 ton and 3/4 ton have the exact same part number. So I am assuming that the drop springs would fit the same for a 3/4 or 1/2 ton. I will know shortly though.. lol wish me luck. I also just got my new roll pans and cab corners, so I will be yanking off the bed, doors and fenders soon.

[Charlesdur]

So on my porch today was a box from LMC truck. I must say that those people really do a great job packing their stuff. Shoot I could pack myself in one of their boxes and be shipped to China and not worry about getting dinged up. Anyways I put on my 2 inch front drop springs tonight and they did exactly that, dropped my truck 2 inches. I searched for a way to do it, #1 raise the truck loosen the ball joint and just lower the a-arm = Didn't work for me

#2 Removed the two U bolts with a little wiggle help from my channels locks and it worked like a charm! Oh I also had to have my 6 year old daughter jack up the A-arm as I adjusted it and the springs back. again a good thing that my wife was at work and doesn't read this post.


Then I put the new springs in and bam.. looks good. I am waiting on the flip kit that I ordered, but I do have the new rocker panels and lower cab corners. Once the rear flip kit comes in I will take off the bed and others parts for the body welding and also have easier access to the rear suspension.

[Charlesdur]

Originally Posted by 67chevemall

While your at it put air bags on the truck and rid the leaf spring
suicide doors will set you up big.

New axles or 8 lug wheels/tires

$0.02

Now that I am getting closer to drop that I want, I might stick with the 8 lug wheels. They are growing on me and I think that they look a little tougher. But once I do the back I will have a much better idea. I will have to make some cardboard templates of 20 inchs rims and tires to see how they would fit on the truck once lowered.

I put bags on the tbird and that broke me, suicide doors though... now that would be something.. I found a kid locally who does some nice airbrush work and real flames paint. I told my 6 year old son that the truck is his when he turns 16 so he wants it black with flames.. I'm sorta of diggin the thought or it might be red with a white top and possible flames... or shoot with my budget primer is sounding even nicer

[Charlesdur]

I put on the "5 inch" flip kit and it only dropped 3.5 inches. Also have in the 2 inch front drop springs. I am actually glad that it only dropped
what it did or the ass would have sagged. Thinking now about some 20's in the rear with 18's up front for a little rake or just a taller 20" tire in the rear. Need to finish the metal work first though. I think that I have gained the most by adding my Unocal 76 ball

[nightmare]

Looks good.

[Charlesdur]

I also found out that it is a DANA 60 rear end!