55.2-59 1956 Do I need to notch?

[BigDaddyK]

Good Morning All,

Finally getting my shop floor poured this week so I can build that and bring my 1956 home to start the project.

My goal for this year is a rolling chassis. I have already purchased a Heidts Mustang II IFS. It came with Standard spindles. They advised this ends up being between a 3 and 4" drop in the front. I want to have my truck level, and I plan on either building or buying a 4 link in the rear. I have a Ford 8.8 for the rear. I am using the original frame.

The question I have is this: Do I need to notch the frame in the rear for the truck to sit level? The stock frame does have a little hump back there, but I don't know if it's enough.

Thanks All!

[dsraven]

most MII suspensions I have seen need a notch or at least a good tough rubber snubber installed. if you don't have at least 3 inches above the axle tube out back then you should either notch it or invest in dental insurance.
I used a ford 8.8 from an explorer in a task force frame that I did. the center is offset so that is one thing to deal with unless you get one from a mustang or something else. there is a write up on the ranger station about shortening the long axle tube to be the same length as the short side and then using a short side axle on that side. dunno if that interests you.
welders series makes some decent 4 link stuff or you can make up your own from their parts, axle brackets etc. thats what i did on the TF frame. I also used a stabilizer bar from a ranger and make brackets to mount it on the axle. I also notched the frame a little on the under side and welded in a sturdy piece to reinforce the area. the frame was fully boxed though. you can see in the pics what I did and maybe gleen a few ideas. i set that frame up for air bags thats what the big plates are for on the outside of the frame. i used a length of pipe to simulate the air bag at ride height. that is a MII front end with 2" drop spindles. the rockers were about a pop can height off the floor at the front edge behind the fenders. I sold that frame so I don't know how it rode, air bags front and rear
if 4 linking you also need a panhard bar, try to make that long and have it sitting level at ride height. that way you get less axle movement from side to side due to the arc that the pan hard bar travels through as the suspension moves up and down.. you can see how long mine was, it was just mocked up and not final welded or braced properly yet in the pics.
on the air bag bracket I made room for a large urethane snubber from the rear of an S10 blazer. they work pretty well and bolt on. you need a corresponding bracket on the axle tube for it to come up against though

[mr48chev]

I'm going to say yes with at least the notch like Dsraven showed . it took me a minute to figure that the brackets on the sides of the frame rails are for bags or coil springs. The notch over the axle and the boxing plates are what you are looking at. other than that it all depends on how low you plan to go and how much clearance you are comfortable with, You may have to have a raised notch over the axle if you intend to be real low but maybe not as much as the lay frame brigade.

The best I can offer is set your lower A frames level (most likely without springs installed. set the front static height at what you intend for it to be. then block the rear of the frame up at the height you intend to have it sit static at and start measuring.

If you don't have the tires or rollers that size that you intend to run you can use this calculator to figure out what the diameter of the tire is https://tiresize.com/calculator/ Then half the diameter plus half the axle tube diameter gives you the alleged top of your axle tube at static height. That will tell you where the axle is going to be in rellation to the frame rails.

Then you have to decide how much clearance between the frame rail and axle is "safe clearance" as there is no carved in stone measurement on that. All I can say on that is that not enough clearance means that the axle may and most likely will hit the frame rail at times.

I'm not intending to suspend my 48 on bags but plan to run a pair of bags as load leveling bags controlled by a level switch that was used on a lot of Cadillacs over the years with air shocks. That way static height will always be the same in theory.

[dsraven]

It is very important to have your tire diameter that you intend to be final with when you are mocking up. Stop at a tire store and get some scrap tires or something that holds air that's the size you want to run. If you buy tires and it takes you a few years to get your truck finished the tires may be outdated by the time you end up getting finished. Haha. Anyway, very important to have the right size tires on when you're mocking it up otherwise if you decide to change tire sizes then maybe the rake angles are wrong and the front end alignments out of whack etc etc

[BigDaddyK]

Appreciate all the replies. I'll take it all in at this point. I haven't decided on Tire size etc. yet. It is on my radar though, but I figured I might as well get the IFS installed and the rear end built (the 8.8 was not posi and 28 spline. I want 31 spline and obv. posi).

[dsraven]

you really should decide on a tire diameter for front and rear and a arke angle for the frame before you install an IFS. this is because the IFS needs to be installed with the lower control arm pivot shafts positioned so they are level, front to rear, and the lower control arms themselves should be set up so they are level, side to side, when at ride height. if you install the same diameter tire on the front and rear then it becomes more of a rake angle issue for setting up the IFS for welding in. if the IFS cross member isn't welded in to keep the geometry correct for the rake angle and tire diameters you plan to end up with then it will be difficult or impossible to set the alignment correct when done.
another thing to consider for a task force truck is that the front fender wheel openings are not symetrical on the front and rear side of the wheel. the rear part angles in such a way that if the axle centerline and tire diameter are not considered and possibly mocked up beforehand you may end up with a set up that looks like the front tires are not centered in the wheel openings. as the truck is lowered the tire generally looks like it is too far towards the rear of the wheel opening. the further the truck is lowered the more exagerated this looks. generally I think most lowered TF trucks set the axle centerline about 1.5" ahead of the stock placement. less lowering would equate to less centerline adjustment.
when ready to start work on the frame I suggest to set the frame up on some sturdy stands and adjust the stands so you get the rake angle you want and also ensure the frame is level side to side. I suggest using a digital level for this because it will give you a screen to read the angle instead of a bubble betwwen 2 lines. a good bubble level is accurate enough but can be decievingly read if you are not looking at the window straight on. the digital level will say the same from whatever angle you look at it from. when setting up the stands try to place them where they wil be out of the way but also not allow the frame to move when dropping out the old front end parts. before installing the new parts recheck the frame angles to be sure things are still where you want them
what I have found to work well is a set of good sturdy jack stands, mine are 6 ton ones, that have a good wide base. I removed the pull up part and tack welded a flat plate across the opening. the plate had a hole drilled large enough to allow 3/4" threaded rod to slide through. then a nut was welded on top of the plate so the threaded rod could be threaded into the top of the stand where the adjustable part used to slide up and down. an extra nut was spun onto the threaded rod to act as a jam nut and keep the threaded rod locked in place at the desired height setting. on the end of the threaded rod that would contact the frame i welded a smaller bolt, like a 3/8 x 1. that smaller bolt fit into a hole in the frame and was held with a nut to ensure everything was locked down once set up how i needed it. this allowed for some very small adjustments to be made during frame levelling and rake angle set up.
I purchased digital torpedo level for a decent price and used my 4ft aluminum bubble level as a longer straight edge to set the torpedo level on so it could span the frame rails. the nice thing about the torpedo level is it is quite handy when checking the angles on things like control arms and other smaller items. it has a magnetic base so it can hang on things while you adjust parts to get the angles you need before tacking things up.
in my case i used the longer level to span the lower control arm pivot shafts, which I installed in their places but left protruding on the front side far enough so that the long level couls span their width. this allowed me to get the side to side levelling done acurately instead of relying on the formed metal crossmember, which may or may not be level when the pivot shafts are level. for the fore to aft check a longer shaft could be used so it protrudes further on the front side to allow the torpedo level to sit on the shaft, or a longer shaft could be used for mock up. this negates the need to assemble, dissassemble, assemble, dissassemble during the set up prior to welding
I highly recommend to get familiar with how an IFS system works so you know what to look for when setting up the new cross member. heidt's used to have a write up in their tech section called "understanding IFS" and it quickly told the most important things to look after and ensure they are right before burning in a cross member. there are other more in depth articles online as well. if not done correctly you could easily end up with bump steer (which changes the steering angles as you go over a bump) or angles that can't be adjusted correctly for good alignment and driveability. you don't wanna end up with a truck that has to be herded down the road, constantly floowing every crack in the pavement or has a ywitchy feel that makes you constantly tend the wheel.
anyway, post up your progress when you get started and ask questions as you go if you need help. lots of knowledge on here if you just ask.

[dsraven]

here is a quick read on IFS
https://www.motortrend.com/how-to/in...nt-suspension/

if you google "understanding independent front suspension there are several pdf's that you can read through. one of them is the heidts one, most are informative enough to get you thinking. because the lower control arm is longer than the upper control arm the system needs to be set up in it's neutral position at ride height otherwise as the suspension moves up and down the tire angle changes. this can mean the tires rub the fenders or they wear off the edges, or it just looks weird

[BigDaddyK]

Originally Posted by dsraven

here is a quick read on IFS
https://www.motortrend.com/how-to/in...nt-suspension/

if you google "understanding independent front suspension there are several pdf's that you can read through. one of them is the heidts one, most are informative enough to get you thinking. because the lower control arm is longer than the upper control arm the system needs to be set up in it's neutral position at ride height otherwise as the suspension moves up and down the tire angle changes. this can mean the tires rub the fenders or they wear off the edges, or it just looks weird

Very much appreciated. The above comment as well, but it'd be a big quote haha.. I know I want 18" rims. I'll start investigating tires then as well. Glad I asked!! Even more Glad you knew!

[dsraven]

Wheel size is not the important part. It is tire outside diameter that is. There are several wheel diameter sizes that, with the right tire size installed, will be the outside diameter you want. Check the link that mr48 posted, it has tabs that give wheel diameters and on each tab page will list tire heights and the sizes that correlate to those heights. Personally I think these trucks look good with the same diameter tires front and rear but some like smaller skinnier up front and huge fatties out back that require some huge wheel tubs in the box etc. To each their own. I chose a 28 inch tall tire and a 17 inch wheel because I have large brakes but want lots of sidewall for a smoother ride. Low profile sidewalls may corner better but on today's roads, traffic and speed limits where can you really do much canyon carving anyway? I'm getting old I guess. As a firefighter I have cut too many cars apart to rescue victims of excessive speed so I prefer a cool looking ride that is capable but not overboard. Nowadays they impound your vehicle when caught, another thing on the list. Afriend of mine owns a newer corvette and says he gets pulled over when others don't because his car looks and sounds fast.

[dsraven]

I looked on the local classified site for some cheap or free tires and found some that still have decent tread (so a real idea of actual size and look can be had) and when I get the truck done I will buy some new ones. since i have been working on the current build for a few years now, between other jobs and projects, a new set of tires could be outdated by the time I am done. I have also seen builds where the owner has bought new wheels and tires in the current fad but when he was actually ready for the road, after several years in the build stage and trying not to get welding slag etc on the new wheels, the fad wheels were not in vogue anymore and a new set of the current fad wheels were ordered.
have you decided on a MII kit supplier? some are better than others and there are questions to ask about tubing wall thickness, ball joint quality (I had some that the rubber boot was simply a push on affair and when the suspension was moved the boot didn't fit the space it was intended to so the inner part of the joint was exposed, might as well not have a boot), steering rack quality, brake component quality, are the rotors a one off or what was the donor vehicle, does the crossmember have a lower control arm bushing pivot shaft fitting that goes all the way through or just enough to hold the ends of the shaft on the front and rear side of the crossmember beam, are the upper control arm brackets part of the crossmember or is it a bunch of components that need to be strategically placed in order to have the whole thing function properly, etc etc. some crossmember kits have the upper control arm pivot built into the crossmember so that takes care of a lot of measuring, fitting, figuring etc. check scotts hotrod site for a look at one of that style
https://scottshotrods.com/front-stee...d-weld-on-ifs/
others give you the parts to weld it all onto your frame along with a vague diagram of what it should all look like. no mention of the antidive angle check, exactly where the centerline of the upper part meets the centerline of the lower part, etc. some upper control arm pivot shafts are held onto the frame and adjusted with T bolts in a slot, others have an upright bracket incorporated so a shim is placed between the shaft and the bracket for camber and caster adjustment. these, in my opinion, are the better set up becasue hitting a pothole is not as likely to adjust your alignment where the t bolt style is able to move, under heavy load, in it's mounting/adjustment slot. guys with the T bolt style will , of course , disagree with that concept but why not buy the best parts you can when those parts have to be welded in. once in they are there for the duration.look at stabilizer bar sizes, how they mount and adjust, shock mounting and how they incorporte them for optimal operation, brake rotor diameter and what generation of vehicle they came from,most are from a '70's vehicle unless you purchase a larger diamer brake kit with better, dual piston calipers etc.
for the rear axle, being a ford 8.8, you may be better off just grabbing another complete axle assembly from a wrecker with the posi, axle diameter and spline count you are looking for. again, check the ranger station site for lots of info on the 8.8. a disc brake set up with the top hat park brake and stabilizer bar, with the rear section of driveshaft for future consideration (unless you plan to swap the yoke for a regular style u joint) came pretty cheap at pick n pull. the stabilizer bar was actually off a tranger not an explorer. when you're there you could also check the suspension snubbers on different vehicles to see the different configurations and materials. like siad, the stepped snubbers from an s10 work well. they actually touch and start to absorb shock before the axle comes close to the frame and are made to do that. an avalanche I had used the same theory and sat on the snubbers a little when at ride height.
on my current build I am using the frame and suspension/driveline from a gmc envoy. big brakes, discs all around, factory 4 link rear with a factory air bag option or coils, strut style front suspension with upper and lower control arms, set up for ls engine or 4.2L inline 6 atlas engine with auto and 4x4/high-low and all wheel drive option. large factory fuel tank inside the frame rails, exhaust system readily available for the aluminum block higher output LS engine, etc etc. i could go on if you want. pm me if you want some more info. a frame swap is not for the faint of heart though.

[BigDaddyK]

Thanks for clarifying. I knew what you meant, I was just outlining the rim size. I do appreciate the tips for getting this going... unfortunately it rained this morning and the shop pad is delayed again.

I think you asked about which ifs I went with? Heists. The product looks solid, but the directions are sparse. I called to ask for some clarification and was refused. That didn't sit well with me.

I'll look into getting some tires soon.

[dsraven]

I think you will find most suppliers have vague instructions. thats why I suggested to you learn up on how the geometry of an IFS works as a whole, so you can get it together and have it work well. the other option is the style that has the upper control arm pivot shaft mount already built in to the crossmember, like the scotts unit has. I believe there are bolt in options as well, which could work well and allow some tweaking if needed before a few welds were placed to ensure it is firmly attached, just a thought.
deciding on the tire outside diameter for front and rear, a rake angle and a ride height is the first hurdle. the second hurdle is to set the truck frame on stands at your desired ride height and place your mock up tires in the wheel openings to see if you have the look you want. this can be done by removing the old front suspension so you have ample space for the mock up tire/wheel combo up front. for the rear you may need to get more creative, like remove a few (or all but the main) spring leaves so the suspension will allow enough drop for your desired rake angle. this way you can see at what height the rear axle needs to sit and actually measure the remaining clearance above the axle to see if you think a notch is required. keeping the main leaf will keep the axle centered at the stock centerline, if the old u bolts arent re-useable just cobble together something to hold things together since it is just for mock up anyway.

[dsraven]

here is a link to show the new and improved TCI MII set up. it shows the crossmember as having the upper control arms built into the crossmember so the correct geometry is built in. it has the vertical pads for the upper control arm mounts, which allow shims behind the pivot shaft for alignment, etc. worth a look for comparison anyway. I installed an older version of the TCI set up, with the old style upper mounts and spring "hats". it didn't go well as I am pretty sure I was shipped the wrong kit. I got no help from the manufacturer or the local supplier so I had to figure out the geometry myself. the one piece crossmember would solve that, whether TCI, Scotts or someone else's. you gotta do your homework for sure. the components are what makes the better kits. sealed ball joints, tie rod ends etc etc

[dsraven]

https://www.streetmusclemag.com/news...ii-suspension/