Howdy moparts!

I’m putting a 512 into a 1989 dakota chassis with a 1954 dodge C-series pickup truck body. I already built a decently strong sure grip rear for two stripe burnouts and smooth street manners but I didn’t decide how to install it yet. My next obstacle is that the truck currently has way too much rake for my taste. The cab is slightly channeled over the frame and I have the front ride height where I want it. The stock dakota 8.25 axle with wimpy stock leaf springs has 9” of travel before it hits the frame. I think I’d like to lose 4-5 inches but I’m a little stuck looking at all the options.

I think if money was no object I would go four link and coilovers. I don’t want to ‘lay frame’ and don’t need to impress people by raising and lowering an air ride. I think the initial expense and continual maintainance of a compressor tank and valve setup is too much for me. Unfortunately $ is definitely a consideration and I have some creative ideas.

The wimpy dakota springs are 54” eye-eye which is the same as a set of xhd 6 leaf A-body springs I already have. My strong, low buck, simple idea is to just mount my new rear on the heavier springs, possibly with slapper bars, and move the front spring hangers up until I achieve the height I’m looking for. The shackle mounts could move too if it looks like that would help keep the front relocation more reasonable or if it looks like it would roll steer.

I don’t have a problem cutting the rivets off the stock hangers, moving them up, and welding them back to the frame. If they stick off the top I can box them in and fabricate reinforcements from 3/16” plate. I’m a little bewildered looking at the ‘drop hangers’ that are for sale online- they look like just a folded tab hanging out in space. This is a part that has to absorb almost all of the force of a launch right?! I’m already nervous about the way the dakota hanger is cantilevered off the outside of the frame- the launch force is trying to rip it loose of the frame instead of getting directed straight forward to the instant center.

I can overbuild this idea pretty easily but in getting it stiff enough to avoid axle wrap with the big block I know I will be making the ride less compliant and more likely to smash and bang over bumps. I won’t totally cheap out on shocks but I’m probably not doing better than ranchos. I could also get a softer ride if I went with the softer dakota leafs and only used the slappers to resist axle wrap/wheel hop but then it might bottom out more with only 4” of travel?

I am also looking at 4-link setups. I have a copy of ‘door slammers’ and the wayne scraba drag race chassis book too but I’m thinking maybe a parallel setup with a panhard bar would be much easier to install than triangulated or angled with no binding for street duty? All I want is no wheel hop and to take out 4-5” of my current 9” of suspension travel. I suspect a lot of the $250 ebay setups are soft cheap steel and bushings etc that would work great on a 200hp mini truck. The two that look good to me are the speedway universal and the competition engineering setups. Especially the CE setup- it looks like I’d have to cut it open and weld it to my axle tube since I already have a brake flange but I really like the idea of it going 360 around the tube instead of just welding to the top or bottom like an axle perch.

The advantage of this setup for me would be that the links would locate the rear, achieving my ride height pretty easily, and seperate the job of maintaining pinion angle and resisting wrap and hop from the job of holding up the chassis. If I did this I could budget for the $350ish 4 link but I wouldn’t have a lot of cash left over for fancy coilovers. I’m sure since I only want decent street manners and am not chasing a 0.9 second sixty foot I could figure out a reasonable coilover option.

If you read this far thank you! I put this in unlawfl because I feel stuck between the drag racing world and the streetrod world on this part of the build. It just seems like most of the easy options for lowering are not going to like big power. I know 600 ft/lbs and 500hp is nothing these days but it is a far cry from a 4 banger mini truck or ford flathead v8!

Got an opinion? An easy solution? Something I didn’t think of? Let me know!

Thanks Moparts!
Rdr

Wow that was my 1313th post must be my lucky day!

I'd do a ladder bar setup

I looked at ladder bars. I’ve seen them where they hook up below the axle- this doesn’t seem like a good engineering option to control wrap unless I keep leafs and install some kind of axle perch floating device to keep it from binding. I’ve also seen where the bar is vertically centered on the axle so it has good leverage, pivots from the front driveshaft U-joint area to minimize driveshaft bottoming and binding, uses coilovers to hold the car up, and even has six threaded rod ends to adjust pinion angle and square up the alignment.

I would just worry that on the street any body roll would try to break stuff with the rear housing acting like a giant sway bar? That’s why I would want a paralell 4-link with infinite instant center so it would be free to move up and down. Or at least that’s what my book and internet learning is saying- if I was an expert I wouldn’t be here asking questions.

I figured with similar prices to get a weld in kit it didn’t make sense to go ladders. They sure look cool though!

Tell me more?

By the way I think what I’m talking about is more commonly called a ‘4 bar’ not ‘4 link’ since it does not have the instant center to center of gravity tunability for racing

And looking at the ladder bars and 4 links/bars that mount only from the front around to the bottom of the axle tube on second thought doesn’t t look like a bad idea anymore- the force looks like it is pushed straight into the top bar while the bottom has much more leverage to resist the pinion rotation. I don’t know which way is stronger but I still like the setups where the axle bracket wraps at least 180°

Caltracs............cheap, efficient and totally street-able.............

Caltracs are the truth for sure.

Really the problem is that I’m considering staying with the leaf springs because I’m wallet limited not class limited. I already have stiff leaf springs that would probably allow me to have 4” travel and never bottom out and I already have a new set of slapper bars I got way cheap that would compliment the leaf springs nicely. So the cost to run leaf springs would be just a day’s work moving the hangers to get my ride height plus all the usual axle swap stuff like perches etc.

I figure if I’m going to spend any money I should do it once and not cheap out too much. That’s why I’m considering the four bar type with coilovers. They would come in around $350 for a decent set I could weld in myself.

I have to get shocks anyway so entry level coilovers shouldn’t be much more $?

Thanks for keeping me thinkIng about different options.

Radar

Caltraks and Vikings with the better valving here.My 3700 lb heap has been 9.3 at almost 147 through the full exhaust with tailpipes.

https://www.facebook.com/dan.tomchik/videos/10212759128164427/

Hemi-itis-
That thing is beautiful and works awesome. It looks like you have just enough weight transfer to hit the tires off the line then it just boogies down straight and smooth.

If this was a 70s unibody muscle car I would be looking at caltracks and mono leafs. I am not because the only reason I’d stay with leaf springs is to be cheap. This thing is a blank slate. There is a ton of room under there and I haven’t even mounted the bed yet. So I can work on it super easily without a lift or spending the day crawling around underneath. The stock leaves live outside the frame rails and inboard of the wheel tubs so the same real estate could be used for a four bar and not lose any room for exhaust or the driveshaft.

My problem is not how to hook with leaf springs- I will probably never dead hook a 512 big block in a 3000lb (or less?) truck on 255/50/17 summer tires.

My problem is what’s the smartest way to drop my suspension around 5” in a way that will be affordable, hold up to 600 ft/lbs, and not act stupid and stutter/hop when I want to lay stripes or powerslide a turn.

I dropped mine over 5 inches with leafs, putting a slider in the rear and dumped the 5 inch or so shackle, took the front half of my mono spring and had it bent, a mirror of how it was, mounted it so the spring came of the top of the front eye bolt instead of under it, 1.12 60 so far on 315's with only a few hits on it, I'm sure it will 1.0

👍 Agree. I put a set on my 512 engined Super Bee, worked great. Also have a set on the 56 Dodge p/u that is setting on a 89 Dak frame. Get the mono leaf springs. You can order them with I believe up to a two inch dropped ride height.

Calvert traction bars are $320, split mono leafs are $430, then I still need shocks and sliders. I just can’t justify spending $1000 to be competitive on the strip for a truck that will never see the strip. What I did learn is that the caltracs are a fan favorite here! I already knew that they worked awesome for putting down big power through leaf springs but I didn’t know they had such a following for street duty.

When I was building my 72 demon it came with worn 340/4spd stock springs, loong shackles, and ugly yellow slapper bars. I tried the xhd six leaf springs with a road race stiff front suspension which was a little harsh but fun. It cornered flat and the tires stayed glued down pretty good. Then I got bored and went with a loose front end and 002/003 leafs which was more fun as a stoplight brawler. I was always curious about the mono leafs but just kept spending money on more power then more braking power haha!

I hate to be the ‘ask a question then ignore the answer and do the dumb idea I wanted to do in the first place’ guy but the calvert deal is just above my budget. For this build I’m trying to do more a mixture of heavy fabrication and using parts I already have if possible.

Thanks for the input anyway. Sorry I’m such a cheap %}^{#|%.

Rdr

Go with your spring and slapper bars and laugh at everyone that says it won't work.

I'm going to go against the grain on this and say to use ladder bars with a good set of double adjustable shocks and a diagonal link
I did that on my old pump gas Duster and it flat work great, hook in a mud puddle in the middle of a rain storm AKA aside that car work great once I got the proper rear shocks on it
Dominic, Thumperdart, car works great also with his set up also

Cal-Tracs work good, but definitely aren't cheap. You can ladder bar it for the same money...maybe less really. I have 2 cars w/ Cal-Tracs, but I'd go ladder bar if I could.

I think that with bars parallel in the forward direction you are going to get wheel hop sure as the sun rising in the East. Look at the No-Hop aftermarket attachments for GM A-body. Those cars had bars with the IC somewhere in front of the vehicle. Axle would hop like mad. The No Hop raised the arm mounting point on the top bars to shorten up the IC. Problem solved.

R.
https://www.qa1.net/suspension/street-performance-racing-suspension-components/gm-rear-anti-hop-bars

Dogdays that is super interesting. I’m learning a ton about all this stuff which is great even if I never do a 4 link I love learning about all this stuff. I have trouble visualizing how the GM style stock 4 link suspensions articulate without binding- the ones with shorter angled top bars. Obviously they work because they made millions of em!

Last night I pulled the dakota axle, shocks, & springs out from under the chassis and started mocking up the 9.25 with xhd dart springs. Man those lower shackle bolts were siezed! The first one I wrestled with a three foot breaker bar trying to spin it out for 30 mins before getting out the hot wrench.

With the suspension removed I found a couple obstacles to overcome- the dart spring is 1” shorter than the dakota spring and it also has it’s centering pin 4” closer to the front eye. I loved that short front segment on the dart it really makes sense for a bunch of reasons.

Luckily I am already changing the leaf mounting position. It looks like if I flip the front hangers, move them up and back around an inch, and drill a 1.5” offset hole in my perches and u-bolt plates to let the axle sit just behind the spring’s centering pin, that my wheels should sit in my tubs just right.

Now I just have to figure out how much allowance I’m going to give the springs to compress with the weight of the truck sitting on them and how much shackle angle I want which will change when it is set down too. I’m thinking probably around 1” but I’ll have to tack it up and see how it acts- it doesn’t help that the driveline and bed won’t be on there. I think if I set it up with no rake as a rolling chassis then installing the driveline will give me the slight rake I’m looking for, even with the mild engine setback I’m planning. I’d rather err on the side of too low- adding a slightly longer shackle is easy but there isn’t really room for a shorter one.

My buddy offered me some ipe wood (brazilian walnut) to do the bed floor. At first I was thinking why would I use one of the densest heaviest woods you can find? Then a puff of steam came out of my ears and I started thinking it might be a great looking and long lasting option that’ll also give me that ‘bags of salt over the axle for snow traction’ effect. 102.5” wheelbase is going to be fun! I’m thinking about Streetwise’s 408 rocky truck but much lower and more torque, probably similar or less HP, and maybe heavier. These trucks came in around 3000lbs but with the dakota chassis and big block who knows? I have an aluminum radiator, top end, master cyl, lighter wheels and tires, 290lb driver haha lotta variables!

I have work today- tomorrow is wrenching day. I have trouble posting pics here since photobucket died but I have a lot of pics in my build thread here:
http://p15-d24.com/topic/47345-512-cid-c-series-on-dakota-chassis-build-thread/

Thanks for all the feedback fellas wish me luck!

Don't do anything permanent welding on the rear suspension until it is ready to run, you know about Mr. Murphy, correct
Do it correctly, the first time

Ha! Loud and clear Mr. Cab!

I am going to set it up with four healthy tack/ 1” stitch welds per side and see how it sits. It’s kind of one of those situations where there are not too many options for where it will go.

As long as the initial setup on the rolling chassis swings the axle in the most vertical way possible (like 2:00-4:00 range) to minimize roll steer, the axle is square to the chassis, and I get a final axle to bumpstop measurement clearance in the 4-5” neighborhood with the springs loaded I will be happy with the hanger placement. If the shackles need to get a little taller after I get to the final curb weight that is an easy problem to fix.

But yeah I never cursed myself out for tacking a weld in the wrong spot. Ripping a nice bead with good penetration and great prep work, but in the wrong spot? That’s time to invent new stronger cursewords!

I do want to do some more research on how my setup might act in terms of instant center and anti squat. In my head the stiff short front segment of my xhd mancini a-body spring will be acting like a trailing arm setup or possibly even a four link where the slapper bars in their compressed mode will also transmit force forward after it’s rotated up.

I’ve read that it’s a common initial tune to put the instant center level with the rear and around 50% of the wheelbase. I know higher hits the tires harder which can give wheelstands or violent loading/unloading hops depending on if your traction is up to the task. Mine will not be the stickiest with 255/50r17 summer tires on the streets of PA so I want a softer hit?

It could be that the higher I raise the hanger the more violently the suspension reacts which would not work out great. Looking at my mockup the IC will fall more around the shifter handle instead of level with the axle.

I can easily see a situation where all these compromises I’m making end up taking away possibilities for better hook and better manners but I can’t see this pile of junk not being super fun to rip around and terrorize the neighborhood. This isn’t a ‘race’ truck but I certainly won’t let any fox body mustangs beat me to 35mph from a stop light!

Then again all our muscle cars the leaf hanger is above the axle so maybe it’s not a bad spot after all?