55.2-59 Flatout IFS install for maximum ride height

[iceman4]

So...I'm probably old school as I prefer to keep my truck ride height close to stock. Will be using the Flatout C4 IFS in my 57. Plan to keep the stock rear leafs and camaro rear for now, "I like the ride height". The standard placement of the crossmember would drop the front too low, about a 5" drop. Don at Flatout
suggested that by mounting the crossmember 1" lower on the frame and coilover adjustments can add back 2" of ride height. A 3" drop works for me. Has anyone tweaked the ride height of the C4 Flatout IFS ? Is anyone using the original rear suspension with the Flatout IFS?

[mr48chev]

Here I thought the whole point of putting a flatout C-4 setup in was to get the truck low and have full suspension.

Finding decent photos of the install on the net is a challenge.

Looking at this one that was in Classic trucks way back when I'd say that you need to do about three steps in the planning stage.

First get a crossmember to ground measurement from someone or several folks with the setup instaled so you can get an average to go by.

Figure how high you want it to ride.

Figure out how you are going to drop the crossmember in the frame that amount. That will probably call for adding something like a piece of square or rectangular tube to the bottom rail of the frame as a spacer but will also be longer than the crossmember to act as support on the back side for the C notch you put in the top of the frame rail to clear the back side and maybe both ends of the upper control arm. Meaning that rather than a C notch under the rail to clear the rack you will have C notches on top of the rail to clear the end (s) of the A arms You would want to run the spacer/bracing back several inches past the notch on the back side to fully put the strength back in and then artfully finish off the ends of it so that they looked like they were designed to be part of the install from the get go.

[daveshilling]

To mount the crossmember higher than factory, you will need to modify the frame to prevent the coilovers from touching the frame, probably modify the coilover mount itself, and maybe verify that the upper arm doesnt touch the frame when fully extended downwards.

If you already owned it, you could mount the suspension, jack up the crossmember until the LCA's are level with the ground, then jack up the frame until you reach the desired ride height to see how much lower you need to mount the crossmember.

Just make sure you don't get projectitis, cause you're the only guy on earth who wants a lifted C4 Chevy truck...so you better finish it!

[MiraclePieCo]

It's an unfortunate result of "groupthink" peer pressure when a guy has to justify his desired ride height.
Nothing is more boring at a car show than to see an endless line of identical vehicles all set up exactly the same.

[iceman4]

Originally Posted by mr48chev

Here I thought the whole point of putting a flatout C-4 setup in was to get the truck low and have full suspension.

Finding decent photos of the install on the net is a challenge.

Looking at this one that was in Classic trucks way back when I'd say that you need to do about three steps in the planning stage.

First get a crossmember to ground measurement from someone or several folks with the setup instaled so you can get an average to go by.

Figure how high you want it to ride.

Figure out how you are going to drop the crossmember in the frame that amount. That will probably call for adding something like a piece of square or rectangular tube to the bottom rail of the frame as a spacer but will also be longer than the crossmember to act as support on the back side for the C notch you put in the top of the frame rail to clear the back side and maybe both ends of the upper control arm. Meaning that rather than a C notch under the rail to clear the rack you will have C notches on top of the rail to clear the end (s) of the A arms You would want to run the spacer/bracing back several inches past the notch on the back side to fully put the strength back in and then artfully finish off the ends of it so that they looked like they were designed to be part of the install from the get go.

Thanks for the info. would definitely add 1" tubing /spacer support to bottom of frame rail. According to Don there is some height adjustability with crossmember placement, approx. 1" with no major modifications. Will verify this again. Thanks

[iceman4]

Originally Posted by daveshilling

To mount the crossmember higher than factory, you will need to modify the frame to prevent the coilovers from touching the frame, probably modify the coilover mount itself, and maybe verify that the upper arm doesnt touch the frame when fully extended downwards.

If you already owned it, you could mount the suspension, jack up the crossmember until the LCA's are level with the ground, then jack up the frame until you reach the desired ride height to see how much lower you need to mount the crossmember.

Just make sure you don't get projectitis, cause you're the only guy on earth who wants a lifted C4 Chevy truck...so you better finish it!

Good info! Not interested in reinventing the wheel or the frame If it requires any more than an upper coilover mount mod. I won't be doing it. I need avoid getting stuck in project purgatory. Truck is my good weather driver, need to complete it by mid February or I will lose the whole year of driving it. This is stance on truck. Original rear springs have settled. Newer springs in front. Front could be lowered several inches.

[dsraven]

what suspension do you have under your truck currently, up front, stock leafs? if you want to add IFS and keep a somewhat stock ride height then possibly look for an IFS systems that has the pivot point for the upper control arm closer to the outside of the frame rail edge. a quick google search will likely eliminate most because that idea shortens the upper control arm in order to keep the proper track width. a short upper control arm means the tire camber goes through a wide range of pos and neg angles when the suspension goes through a complete cycle from lower droop to upper jounce stops. a fix for the whole thing is a narrowing of the frame to allow a regular IFS to work. something like this set up from GSI. just for ideas sake. this, of course, would eat up space between the engine and frame, causing new issues/problems. of course their pic shows a lowered truck. the idea is what I was trying to show.

https://www.gsimfab.com/1955-1959-ch...4286_8808.html

I think the roadster shop idea is what most are talking about in previous posts. where the upper frame rail is cut down. this is their REVO frame. nice. just need to win the lottery. again, it's the idea I was trying to show.

https://www.google.ca/search?q=55-59...fDlD_2S9fDQmTM

[dsraven]

sorry, musta copied the wrong link on the last one. try this.

http://roadstershop.com/product/full...-truck-chassis

[mr48chev]

Two options for an independent front end that would better suit your needs may be a Jag XJ that can easily be set in at any ride height you want or possibly the Industrial Chassis Inc Dakota crossmember for TF trucks if Steve ever gets around to making them again. The picked up the shop and moved and combined with another shop and the Covid thing has really hindered progress of getting the new shop all set up and in full production. Word is that his crossmembers have a higher ride height than many other outfits do but that would have to be researched.

[whitedog76]

I had the same idea as you on my 54. I don't want to drop it all the way to the ground, but a slight drop would do.

I used a MII crossmember and added 1.25" of material to the lower crossmember and trimmed the same amount from the upper hats.

With a stock style MII setup, it is going to limit the total castor. The upper a arms will hit the frame if rotated all the way to the rear. Since I am stuck in build purgatory, I can't say if it's a really big problem or not. 1" of spacing would've been a whole lot better than 1.25.

https://67-72chevytrucks.com/vboard/...d.php?t=774730

[daveshilling]

Originally Posted by MiraclePieCo

It's an unfortunate result of "groupthink" peer pressure when a guy has to justify his desired ride height.
Nothing is more boring at a car show than to see an endless line of identical vehicles all set up exactly the same.

A guy doesn't have to justify his ride height to anyone. Someone is asking how to add a suspension setup from a corvette-a very low car- using a kit designed to lower the truck. So naturally, it raises some questions about why this kit would be used from a practical standpoint. Does that make sense?

Being intentionally different just to stand out at a car show is lame anyways. If you have to think about how to be different, then you aren't.

[mr48chev]

Originally Posted by daveshilling

A guy doesn't have to justify his ride height to anyone. Someone is asking how to add a suspension setup from a corvette-a very low car- using a kit designed to lower the truck. So naturally, it raises some questions about why this kit would be used from a practical standpoint. Does that make sense? .

I'd have to say that was my original point in post 2 even though some took it wrong. The Flat out crossmember doesn't really work well with the close to Stock AD truck height nor do many MII setups.

Probably the best crossmember to have independent suspension, disk brakes and power steering with and maintain close to stock AD or TF truck height without hassles would be a Jag XJ front end. In truth it might work better installed in a stock height truck than it does in a low truck because you would have plenty of steering rack clearance with the suspension setting down lower from the frame rails. It could even be mounted on a TF using the complete Jag subframe piece with the rubber bushings if one wanted to do that rather than trim the scabs and weld it in. Outside of coming out of 4000 lb cars and being plenty stout along with being unbolted from the donor as a complete unit probably the best part of the XJ suspension is that the spring pockets are completely outside of AD inner fenders and may completely clear TF inner fenders leaving a stock look in the engine compartment outside of steering shaft location.

[dsraven]

Iceman, I hope you didn't take my posts ge wrong way here. I have always said, it's your truck do what YOU want. I like to give options and explain different mechanical reasons for my points, but in the end its YOUR choice. Just keep it safe. I apologize if I came off sounding like you need to do this or that. I didn't mean to.
Keep us posted on your choices, we still like seeing the pics, maybe pointing out something that could be done differently or giving a good old internet slap on the back for a job well done.

[iceman4]

Originally Posted by dsraven

Iceman, I hope you didn't take my posts ge wrong way here. I have always said, it's your truck do what YOU want. I like to give options and explain different mechanical reasons for my points, but in the end its YOUR choice. Just keep it safe. I apologize if I came off sounding like you need to do this or that. I didn't mean to.
Keep us posted on your choices, we still like seeing the pics, maybe pointing out something that could be done differently or giving a good old internet slap on the back for a job well done.

Not at all! I appreciate hearing the opinions of people that have been there done that. I bought the truck 6 years ago as an "Almost completed project"...Almost completed project is a nice way to say "Unsafe to drive "LOL. Truck came with sbc 350, TH350 trans, and a 68 camaro rear. 54 car front hubs to get the
5x4.75 lug pattern. I've been working on it Winter months and Driving it, good weather days , the rest of the year.. New wiring, LED lights, Upgraded to front disk power brakes. new front leaf springs, moved gas tank to the rear, And small things to make it a more user friendly driver with todays roads and distracted drivers. I have looked at different ifs power steering options but have decided I want to keep it as much Chevy as possible. The two popular options being a 70s camaro front clip or C4 suspension. I had a 75 Camaro in the 70s when I was in high school. Handled well until I did the cool thing and added rear shackles to raise the rear to get the drag car stance. Decided to go with the C4. The Flatout front wheel CL will sit at 2 to 2.5" above the bottom of the frame.
My trucks newer front springs front wheel CL is 3" bellow the frame. I would like some rake so a 3" drop should work . Any more and I'll have to lower the rear some. The title of the thread may be misleading. want to install the cross member lower as long as it doesn't require major modifications to the frame. When I start will post update.
Thanks Mike

[57tailgater]

I'm not going to bash about your ride height as I am with you and would prefer my truck not to be sitting in the weeds as well. Any reason why you're set on Flat Out's kit? I think Heidt's makes a couple of kits that would keep you in the stock or slightly lowered height without the mods. Just a suggestion.

[dsraven]

just be aware that if you drop the front end 3" and install the new parts level with existing frame the geometry will be off and it may drive like your old camaro did. the caster will be way off. the way around that is to set the truck up at the rake angle you want and then install the front end to sit level as it is engineered to do. maybe ask those questions when you purchase the parts to get detailed instruction on exactly how to do the install.
a quick mock up would be good to do to see if you like the look at the rake angle you are thinking. simply get a dimension of the front bumper to ground at the stock height, then jack it up and take the front wheels off. let it back down to the height you will be at when the new front end is installed, block it there and set the wheel back in the fender opening. it is also a good way to see what your axle center line should be so your new front end will be in the right place. since the fender openings are angles on the rear side and not on the front side of the opening it can make the tire look like it is being stuffed into the back of the wheel opening as the truck is lowered down.
too much rake will put more weight on the front axle and the rear wheels may spin easier and also skid easier when braking.
so right now the axle is 3" below the frame, you are proposing a 3" drop so the axle will be level with the bottom of the frame, correct?
will your tires be able to turn without hitting the fenders when you go over a bump?
what is the tire size recommended for the corvette front end they will be selling you? different tire outside diameter may have an effect on the steering geometry, scrub angles etc.
will the track width be the same as the original axle? will you need to change the rear axle wheel bolt pattern to match?
just some thoughts.
nice looking truck. I am partial to blue though

[dsraven]

what I meant by "level with the existing frame" in the 1st sentence above, is level fore to aft. if the frame has a big rake and the new front end is installed with the same rake then you may have steering issues that will be beyond the limits of adjustment.

[iceman4]

Originally Posted by 57tailgater

I'm not going to bash about your ride height as I am with you and would prefer my truck not to be sitting in the weeds as well. Any reason why you're set on Flat Out's kit? I think Heidt's makes a couple of kits that would keep you in the stock or slightly lowered height without the mods. Just a suggestion.

Yes, there are tons of IFS options several would be a better choice to keep a higher ride height. Saw a TF truck that had a Volare clip. Totally adjustable from low to high with its adjustable Torsion bars. Been looking at builds for quite a wile, The C4 is not super low, if I can get back a couple of inches it should be close to where I want it. At the end of the day going with the Chevy option is also important . If I have to drop the truck more than I would like, so be it.

[iceman4]

Originally Posted by dsraven

just be aware that if you drop the front end 3" and install the new parts level with existing frame the geometry will be off and it may drive like your old camaro did. the caster will be way off. the way around that is to set the truck up at the rake angle you want and then install the front end to sit level as it is engineered to do. maybe ask those questions when you purchase the parts to get detailed instruction on exactly how to do the install.
a quick mock up would be good to do to see if you like the look at the rake angle you are thinking. simply get a dimension of the front bumper to ground at the stock height, then jack it up and take the front wheels off. let it back down to the height you will be at when the new front end is installed, block it there and set the wheel back in the fender opening. it is also a good way to see what your axle center line should be so your new front end will be in the right place. since the fender openings are angles on the rear side and not on the front side of the opening it can make the tire look like it is being stuffed into the back of the wheel opening as the truck is lowered down.
too much rake will put more weight on the front axle and the rear wheels may spin easier and also skid easier when braking.
so right now the axle is 3" below the frame, you are proposing a 3" drop so the axle will be level with the bottom of the frame, correct?
will your tires be able to turn without hitting the fenders when you go over a bump?
what is the tire size recommended for the corvette front end they will be selling you? different tire outside diameter may have an effect on the steering geometry, scrub angles etc.
will the track width be the same as the original axle? will you need to change the rear axle wheel bolt pattern to match?
just some thoughts.
nice looking truck. I am partial to blue though

Good info! I've been kicking around most of them. Will get the truck in the anticipated stance and see if its to my liking or any obvious clearance problems. I'll be using a ''84'' C4, smaller rotors so will keep my 15" rims for now. Bolt pattern is 5x4.75 ,same as Camaro rear. Will check rake angle and see if 1 or 2 degrees will cause suspension issues with the C4. Dropping the rear is always an option. Thanks

[iceman4]

Just want to post an update. Installed the flatout crossmember 1" lower and with the coilover bracket installed in the higher ride height position, front end sits about 2" higher than a normal flatout crossmember install. Got it aligned and after putting some miles on it, all is good so far. Ran out of time to address the rear until next fall, when my seasonal business slows. The rear is still oem leaf springs and will need to drop it 2-3" to get the stance I want. The first photo is the original ride height and the second is after the flatout install.

[58 pache]

Looks real good man. need to get mine.

[mr48chev]

That's a good looking truck. You nailed centering the wheel in the opening too. That is something that a lot of guys miss the mark on when putting independent on a TF. Well done.

[iceman4]

Originally Posted by mr48chev

That's a good looking truck. You nailed centering the wheel in the opening too. That is something that a lot of guys miss the mark on when putting independent on a TF. Well done.

Thanks, Many hours of measuring and mocking up to get it where I wanted it. Wife was questioning my sanity LOL.