1965 frame back half help?!

[Dwolfe]

Ok guys so i have decided to back half my truck, im going to lay frame , so the vertical distance from the bottom of the 2x4 steel tube to the axle will be 10 inches. No i have marked were im going to start my back half but im trying to be as perfect as possible and i dont know exactly what angles to cut the tubing were the diagnol meets the straight half of tubing. I know it depends on what angle i put the beginning of the frame at but any ideas on which angle will
The tubes line up even? Or will they not? Thanks!

[tinydb84]

I'm realizing I don't think I responded to your other question before.

I would use CAD (aka cardboard aided design). I am a big fan of putting stuff where it will be (or likely be) that way you don't run into an issue later with stuff not fitting.

Just a few tips if you aren't doing it that way. Remember your angles on your cuts need to be half of whatever joint measurement you want. Ex: cut at a 45 degree to make a 90 degree joint. Your axle will move forward as you air down so make sure you have enough clearance for the air. You can measure it or calculate it once you know the length of the bars.

I personally would cut after the second bed mount and backhalf from there. That way you only need to locate two sets of mounts and not need to rebuild that cross member. Plus that cross member will help keep everything straight.


If you wanna go super simple just make a notch that fits over the current one. You can cut it in and weld it before cutting the old notch out.

[Dwolfe]

Originally Posted by tinydb84

I'm realizing I don't think I responded to your other question before.

I would use CAD (aka cardboard aided design). I am a big fan of putting stuff where it will be (or likely be) that way you don't run into an issue later with stuff not fitting.

Just a few tips if you aren't doing it that way. Remember your angles on your cuts need to be half of whatever joint measurement you want. Ex: cut at a 45 degree to make a 90 degree joint. Your axle will move forward as you air down so make sure you have enough clearance for the air. You can measure it or calculate it once you know the length of the bars.

I personally would cut after the second bed mount and backhalf from there. That way you only need to locate two sets of mounts and not need to rebuild that cross member. Plus that cross member will help keep everything straight.


If you wanna go super simple just make a notch that fits over the current one. You can cut it in and weld it before cutting the old notch out.

Awesome advice ! I think i will, so pending on my bottom angle that will find my top andgle then cut that angle in two and thats my cuts correct? Also wont i have to take that middle crossmomber and cut it in half and make it taller for drive axle clearence?

[tinydb84]

the way you tie into the frame is up to you but it will determine how you make your first cut. I still think you would be best served using cardboard to set up the backhalf and then copy it for your cuts.

You will have to cut that front crossmember. Take a look at the way that Porterbuilt makes a notch for it for ideas. Some people use tube but I don't like the way it looks with the flat steel.

You can also just make your own out of rectangle or square tube and use it for your 4 link or to triangulate your notches.

Spend some time looking at backhalfs before you start planning or cutting.

[Dwolfe]

Originally Posted by tinydb84

the way you tie into the frame is up to you but it will determine how you make your first cut. I still think you would be best served using cardboard to set up the backhalf and then copy it for your cuts.

You will have to cut that front crossmember. Take a look at the way that Porterbuilt makes a notch for it for ideas. Some people use tube but I don't like the way it looks with the flat steel.

You can also just make your own out of rectangle or square tube and use it for your 4 link or to triangulate your notches.

Spend some time looking at backhalfs before you start planning or cutting.

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[Dwolfe]

Great! So today i spent hours with a another fabricating buddy if mine and decided to go after the second bed mount. I laid out all my cardboard and sized it up to the tubing im using. Then cut and went at it! Let me know what you think of design tomorrow will have all cut and tacked into place! Pretty simple ! After i tack up the rear half its double/ triple check all levels and meaurements then weld in . On the 4 link part whats the best Direction to mount the two upper small bars? To the cross? The kit i got is ment to run from side frame to axle. Also what angles should they be at ride height? Thanks take a look!
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[Dwolfe]

Check it!

[tinydb84]

I'd drop the frame down after the axle that way you can mount your panhard or watts to it. You can also mount your gas tank easier that way.

Post a picture of your 4 link so we can see what mounts you have.

[Dwolfe]

Originally Posted by tinydb84

I'd drop the frame down after the axle that way you can mount your panhard or watts to it. You can also mount your gas tank easier that way.

Post a picture of your 4 link so we can see what mounts you have.

Okay will do in a bit! So your saying instead of going straight just go back down instead of straight back? Makes bed mounting way easier too

[Dwolfe]

I coud also just go back down into the back and reattach to the stock frame? Or will that look dumb?

[tinydb84]

Originally Posted by Dwolfe

Okay will do in a bit! So your saying instead of going straight just go back down instead of straight back? Makes bed mounting way easier too

That's what I would do. Gives your more mounting space without having to hang everything under the frame.

Originally Posted by Dwolfe

I coud also just go back down into the back and reattach to the stock frame? Or will that look dumb?

Cut some cardboard and mock it up to see if you like it.

[Dwolfe]

Originally Posted by tinydb84

That's what I would do. Gives your more mounting space without having to hang everything under the frame.



Cut some cardboard and mock it up to see if you like it.

Mocked up some more today and made sure all my measurements were good so i would lay frame and more measuring! For deciding to go back down into the stock frame, but im going to trim the rear to 2" and box it all in made the measurements for that too today. The worse part is making sure you get all the angles right im worried mine might be off cuz the cardboard flexs 😅 Any tips? I figure my point were each sloped piece meets is 110 so each piece needs to be 55 to get a flat level surface. Right? Also the rear seams to be higher than the rest of frame if so my back piece will
Be shorter. Attached some pics of the 4 link to guys!

[Dwolfe]

Pics

[tinydb84]

Originally Posted by Dwolfe

The worse part is making sure you get all the angles right im worried mine might be off cuz the cardboard flexs �� Any tips? I figure my point were each sloped piece meets is 110 so each piece needs to be 55 to get a flat level surface. Right? Also the rear seams to be higher than the rest of frame if so my back piece will
Be shorter. Attached some pics of the 4 link to guys!

Measure the angle of the joint using the flat sides of the notch.

As for the 4 link, the brackets look to be made so that the triangle comes together at the rear. You might need to build a bar over the top of the rear to get the necessary triangulation you need to keep it centered (I recommend you do not weld the tabs to the center section directly).

[Dwolfe]

Originally Posted by tinydb84

Measure the angle of the joint using the flat sides of the notch.

As for the 4 link, the brackets look to be made so that the triangle comes together at the rear. You might need to build a bar over the top of the rear to get the necessary triangulation you need to keep it centered (I recommend you do not weld the tabs to the center section directly).

Gotcha! And as far as the 4 link goes soo dont weld directly to the axle tube? Weld a tube style bar to the axle then weld to the brackets? The bottom bars have to be set parralel at ride height what about the smaller ones? Certain degrees also?

[tinydb84]

You can weld to the tubes just not the center section (its cast iron).

Bottom arms parallel to the ground at ride height. Upper bars 3-5 degrees down towards the front.

[Dwolfe]

Awesome info! Saving me so many headaches!! Just do the stock ride height correct? And with my truck leveled out the pinion angle is about 5-6 degrees so with it down its prob 2-3 is that were i shoukd keep it when i set it?

[tinydb84]

Originally Posted by Dwolfe

Awesome info! Saving me so many headaches!! Just do the stock ride height correct? And with my truck leveled out the pinion angle is about 5-6 degrees so with it down its prob 2-3 is that were i shoukd keep it when i set it?

Leaf spring cars typically have about 2 more degrees of pinion angle than a 4 linked car (in becomes more parallel under load).

I would measure my trans output and match it when installing your 4 link.

[Dwolfe]

Originally Posted by tinydb84

Leaf spring cars typically have about 2 more degrees of pinion angle than a 4 linked car (in becomes more parallel under load).

I would measure my trans output and match it when installing your 4 link.

So i put the bars parrell to the ground , and small ones down 4 degrees . So to start when im down with notch, put a jack to the rear end and hold the diff were its at after measuring were its at exactly. Then get rid of leafs and the front crossmember. Weld flat to the frame were about the smaller links will go. Then line up the 4 link? Sound right? Just trying to do it right will have pics up soon of notch

[tinydb84]

I would pull the leaf springs and do it all on jack stands. Buy a set of aluminum trailer jack stands. They are cheap and adjustable to get everything level and where you want it.

Rest of it sounds fine. I would double check to make sure you have enough triangulation on the rear before welding the upper bars in.