67 c10 shortbed, how do you make it hook?

[racindego]

I have a 67 c10 shortbed that i am trying unsuccessfully to drag race. heres my situation: I have stock rear control arms with coil overs, 150 pound springs. The truck has 29.5x11.5x15 hoosier quick time pros, brand new, with 15 psi. The truck is currently mini tubbed and I dont want bigger tires. My pinion angle is very close to dead on where it should be. My front susepension consists of tubular a arms and shortened springs, very soft setup. My fuel tank is directly over the rear wheels and my battery is in the back passenger side corner. The truck has a full 12 point cage. I would estimate the weight to be 3400-3500 pounds with me in it. I eventually want to come off my trans brake at 4800-5200 somewhere in there. My motor makes somewhere around 650 horsepower. Right now, at the track, my launch looks more like a second burnout. Truck barely even moves when I come off the brake, even at lower rpms. am i missing something? I know people make these trucks hook, I have seen pictures of them with the wheels hanging. Do i need a four link? Where do I start?

[68LSS1]

Here's where you need to go: Hot Rods to Hell I got my kit yesterday and it looks like a great set up. The only way I'd 4 link it would be if I didn't drive it except for the track. I should be at the same horsepower level as you but hopefully a couple hundred pounds lighter. One last thing, what gear are you running with those 29.5, what's your trap speed and what rpm when hitting the high end? Can you take some gear out?

[racindego]

i amrunning 5.40 gears in the truck. I need to turn the engine to 7800 plus in order to make power so i will only be taking gear out if I decide to spray it. Thanks for the link

michael

[Primed67]

I'd suggest either a ladder bar set up or a 4-link with coil overs. I currently have a coil over set up with the stock trailing arms also. I'm running 15 x 12 wheels with M/T 29.0 x 15.50 x 15 Sportman Pro's. The coil over setup helped tremendously but I still have a spinning problem. Of course I have never replaced the 36 year old trailing arm bushings. I was told that that should help. Once I get some money I'm going to do a 4-link.

I have a buddy that had a 72 with a nasty big block and a 4-link and he never had a problem. I think he was running low 9's on the motor.

If you want to keep your current setup with the trailing arms then I would suggest that you replace the bushings if you haven't already and that you play with your pinion.

[racindego]

my bushings are definately old crusty originals that probably need to be replaced. I will give it a shot if I dont just go with a four link. thanks for the ideas, guys

michael

[racindego]

and also, does anyone know why the search feature doesnt work? Im sure i could find a lot of info in past posts, but searching is disabled or whatever

michael

[Primed67]

I believe that it has been temporarily disabled.

[nate68]

let us know how the hot rods to hell kit works for our trucks

[boraxman]

Originally posted by nate68
let us know how the hot rods to hell kit works for our trucks

And how much $ they are.

[Primed67]

I think he told me $1,000 plus shipping.

[68LSS1]

I'm thinking about 960 for the kit 1040 shipped.

[BigPun76]

Your stock trailing arms should be able to hookup just as well as a 4 link. Your front mounting point (where the arm hooks up to the crossmember) is probably too high up. If you were to lower the mounting point (move it closer towards the ground), you move your "pickup point" further forward. It's hard for me to explain how it works, but if you were to draw an imaginary straight line from your rear axle where your arms connect up to where the line would contact your frame, you would see that the point is well behind the rear of your motor/trans. By moving the front mounting point lower, you extend that line further up your frame and provide more leverage, therefore more pressure is applied to your tires and the ground. Sorry about the rambling... Mud racing provided lots of information about rear suspension setups and how they work.. hehehe

[SCOTI]

BigPun.... I agree, but what if the truck is lowered? That would already change the I/C leverage compared to stock height would it not?

[68LSS1]

No it wouldn't. The basic geometry remains the same. The Hotrodstohell kit does also relocate the forward mounting point of the trailing arm down. I can go into more detail here if wanted-it wouldn't be hard to do.
BigPun76: I like your thinking. Finally someone else who realizes the potential of trailing arm suspensions.

[BigPun76]

Thanks, 68LSS1. Like mentioned above, NASCAR using trailing arm suspension. Ladder bar suspensions and trailing arm suspensions are basically the same thing but normally ladder bars are more compact (shorter) than "trailing arms." Heck, most Pro-Mod drag cars use a swing arm suspension that is basically the same as above mentioned and they're putting out 2500 hp! So I believe trailing arms will work just fine!

[racindego]

thanks guys, great advice and I will definately look into it. my only concern is that by lowering the front mounting point of the control arms, i will essentially straighten them out, since they are angled slightly upward now, and cause my rear axle to be shifted to the rear more then it already is. I will have to find a solution to this, but that shouldnt be to bad. Do you guys think building new trailing arms from 2x3 steel that they use for chassis work is a possible solution?

michael

[68LSS1]

I think the stock ones will be fine. I am contemplatong "boxing" mine though. If you are worried about changing the pinion angle you can get shims (wedges) for between the arms and axle seats. As for the front you can remove the rivets holding the front arm mounts, slide the mount down so the original top holes pick up the middle and weld it up. The mount will hang a little lower than the crossmember it attaches to and I would weld a little angle gusset here. Keep in mind with the trailing arms they don't give like leaf springs so as you load the rear end, the pinion will try and turn down, not up like leafs.

[darcane]

Hold on there... You don't want to move the Instant Center forward or down as BigPun76 is suggesting. Doing that is exactly the opposite of what you want. Read this.

The front pivot point for ladder bars (which is really what trailing arms are) is the instant center. Moving this point upwards or towards the rearend will give you more anti-squat and will plant your tires better when you launch. Since you are spinning your rear tires, this is exactly what you want. However, it's not real easy to do using the stock suspension.

You might want to try contacting this guy:

You can barely see the stock trailing arms in this pic, and he's obviously hooking up pretty well. The site doesn't say too much about his setup, except that it is "stock" trailing arms (I would guess they are at least reinforced with something like this ) and coil overs.

[68LSS1]

Well, I tend to agree with BigPun76 and I'm probably biased as I have the Hot Rods to Hell kit which does have you lower the front mounting point down on the trailing arms. I did a lot of reading also (and was originally going to do the triangulated 4 link). I'd suggest calling Hot Rods to Hell and talk to them. They answered all the questions I posed to them. I don't know if just lowering the trailing arms would be sufficient but I'd try that along with some coil overs. The kit I got comes with screw jacks and springs.

[darcane]

I've been having some trouble with getting to that hotrodstohell site. I finally got there... is this the kit you are referring to? I'm not seeing anything in the kit that changes the mounting points of the trailing arms. It looks like it's just a different panhard bar, different shock mounts, and springs with screw jacks. Is there some other kit you are referring to?

[68LSS1]

No, that is the kit. The kit doesn't come with different attach brackets. You remove the 6 rivets from the original bracket and drop it down so the top two holes in the bracket are now picking up the middle two holes. Weld it up. It does come with angles to weld between the trailing arms and crossmember to restore any lost strength. I talked to the guy 5 or 6 times before I decided to go with his kit. He's installed them on a lot of these trucks, including a blown big block with excellent results (my measurement here is 60 ft times). Personally if this even works only AS WELL as a 4 link I'll be happy because I won't have to give up the ride/handling that I would with the 4. Give me a year to two and I'll let you know how it handles 675rwhp, a manual tranny and the gas.

[nate68]

i would like to reinforce my trailing arms but i'm sure it could be done for a lot less. I dont need new bushings or U bolts.
I know someone who is a professional welder that could do all the welding for me.
I have heard that some people have just welded the center seam on the top and bottom. I dont know if that is better or not

[68LSS1]

After reading the instructions a little closer I saw that I was wrong on how far the front trailing arm mount is moved. The six rivets are removed and then you drop the mount down using the middle holes in the bracket. Drop it down so the middle holes in the bracket line up with the bottom holes in the cross member.

[racindego]

after doing more research, i am still a bit confused as to which way to go with the trailing arms. the hot rods from hell kit obviously lowers the mounting point, but this seems to go against all the basics of suspension setup. Moving the mounts is no problem, just which way do I go?

michael

[68LSS1]

Give HTH a call and talk to them. I called him today and he's trying to get the guy with the blown big block to post his feedback and maybe some pix. I asked about boxing the trailing arms and he said not to. He did say I could weld a 1/8" plate on the TOP and BOTTOM of the rear of the trailing arms (where the axle u bolts are) but not to box it. He said you don't want to make the trailing arm too rigid.

Edit for: he did say I could run maybe three weld beads on the seems of about 1 1/2" long top and bottom, but he wouldn't do much more than that.