I installed a TCI Mustang II on my 1956 f-100 with a 302 and C-4. Works good.

I'm sure the Y will fit nicely. YOu will enjoy your truck ride, handling and braking much more. However, my ride is an improvement but it still rides like an older truck vs. a new model truck ride.

Tacomalight

 

Thanks for the info.

AP73

 

Is anyone out there running a Y-block with a Mustang II IFS? Nobody has answered his question yet.

I checked the galleries of folks who answered here and everyone is running something other than a Y-block (me included). AX came closest to answering with his reference to pan or crossmember mods that might be required.

Anyone else?

 

I checked my 54 car (org 256 cu in Y block) and it has a front sump. You need to have at least 1 inch clearance to crossmember and or rack unless you will be using solid engine mounts.

The Mustang 2 was made from 1974 thru 1978 and they had a 302 V8 in the cobra version. It was placed in some what the same location that we now place our engines.

The rear strut was the forth control arm mounting point and was used to help control the twist of the lower control arm when the wheel goes into recession (hit a pot hole wheel moves rearward along with vertical which causes the twist).

The fox platform (made from 1979 thru 1993 then renamed sn95) has a strut front susp. (no upper control arm, spring is mounted to strut).

I build a 56 f100 with a 351W/C6 using a aftermarket crossmember and stock must control arms with the strut 15 yrs ago and it is still holding up just fine, I happen to like the Volare susp better but thats just me.

It can be done but it may take a little extra engineering to mount the Y block, it sure would be different and have one he** of a cool factor.

Good luck and enjoy

 

First, a disclaimer, I don't have a Mustang II IFS in my truck. But, nonetheless, I think I can help.

The frame of the 53-56 trucks seem to have been designed like the earlier Model A and older chassis; it's part of the 'suspension'. It's intended to bend, twist, and absorb road irregularities. I think the truck was intended to be used on farm fields, and in Korea during that war, where the roads were rough.

I have a 53 Studebaker quarter ton truck and it has a beefy, stiff frame, cross braced, boxed, heavy as hell.

So the beauty of the F100 is that it's light and has a compliant frame.

Part of the layout of the flexible 53-56 F100 frame is the mounting of the engine. It mounts by the bellhousing, and off of the timing cover in the front. The transmission does not mount on a crossmember. This drivetrain layout allows the frame to flex without the engine binding. Also, notice that the back of the cab is hung on little arms that allow the cab to ride on the twisting frame without binding.

I think that keeping this light, flexible frame design in mind when you start modifying it would be an important consideration.

My recommendation; keep the original engine mounts. And, be sure to use struts to help counteract braking forces. There have been a couple of accounts of failing chassis members, probably due to the torsion from braking forces. I'm talking about the strut that runs from the lower ball joint on the lower A-arm, forward to the frame. Look at a stock suspension on a Fox Mustang to see how it goes. This often gets left off because it clutters the look of the suspension.

 

I didn't disagree with anything you said until the last paragraph. The lower suspension members on the fox chassis were originally designed as cheap and lightweight replacements for a true lower A frame for the Pinto. The Pinto chassis was revamped to become the fox chassis when the original Mustang sales started to drop off and all the American car manufacturers were in deep financial trouble and looking at their parts bins to come up with low priced but still high profit vehicles to compete with the imports. That suspension was NOT one of Ford's "better ideas" and was rightly put in an early grave along with the MII. That system is not used on any of the kits built by the major aftermarket manufacturers not because it clutters up the look, but because it doesn't work, is unsafe on a 4000# vehicle, and they've replaced it with a true lower A frame or double wishbone setup. Frame flexibility is not an issue or even very desirable for good handling and driving on modern paved highways.

 

Well, the frame is what it is. Either you work with the design of the frame, or you redesign and rebuild the frame into something else. It's true that it doesn't need to be flexible for today's roads, but it is light in weight.

The two alternatives to using the existing frame the way it is designed, are; box and cross-brace the frame to stiffen it, which takes a lot of work and adds a bit of weight, or ignore its design and make a squirrely vehicle.

The original Mustang II was a unibody design, with a flexible body/frame. The Fox chassis is similar. Maybe it's not the best autocross setup around, but it gets the job done. A smallish crossmember with a Mustang II rack and some custom A arms is an ok way to add an IFS, but leaving the strut off seems like really bad juju.

 

Actually the Progress ifs kit that I bought approx 15 yrs ago did use the strut!

The new kits don't have two mounting points for the lower arm just a bracket in the middle to allow the arm to twist in the right conditions.

pcmenten is correct about the strut.

 

the strut in question is very similar to the LTD/Lincoln frames that I like so much and it is designed to work in a rigid frame situation. I think (mho) that adding IFS to these trucks without addressing the flexi-flyer frame situation is a huge mistake. I certainly don't want to step on anyones toes but I feel, as I have stated before, that the MII is too light for these trucks, at the same time I agree with Chuck that a little structual updating of the MII control arms is advisable as well adding to the safety factor.

PS merc, I think that Progressive has discontinued that MII kit

 

Actually any MII kit I'd even consider using has two spread pivot points for a true lower wishbone, I'd NEVER use the original single pivot/strut lower control arm, especially without the strut, or the original upper A arm for that matter. As Tim says it's WAY too light for our trucks IMO. Today's kits are MII in name only, with only the spindle/upright and steering rack ever seeing a Ford parts shelf. Pcmenten, you're right about the handling that setup does some pretty wild things with the alignment, especially when you hit a bump.

 

Thats all well and good but the pivot points are hanging outside of the welded bracket, you still are mounting the lower control arm thru a bracket that allows the lower arm to rotate and not in the direction that you want. I too feel this susp is to light for these trucks thats why the one I have now has a Volare but I do think the LTD would be even better.

AX: You and I will never agree on what time of day it is so why don't we just agree to disagree.

FF56: You may be right I did the Must 2 because I was a Vehicle office package designer for Ford for over 30 yrs and thought I should use a Ford suspension, well I did and hated it from day one. It was to narrow even with the rack extended 2 inches per side, put wider wheels on and it seemed to load the susp making the streering feel heavy. The guy who bought the truck thinks it is great, so to each his own.

 

without becoming too long winded over this (it may already be too late) extending the tie rods/steering rack just makes the problem worse, offset wheels just move the contact patch of the tire further away from the vertical pivot of the upper and lower ball joints and aggravate the situation. Those are some of the reasons that the Progressive kits don't work all that well. None of this is to say that the design doesn't work, the Heidt and TCI kits are based on the MII but have had the hiccups designed out. thanks for listening, I'm done

 

Extending the rack pivot points just followed the 4 inch wider track (all suspension points moved 2 inches per side just like all of the susp kits for the F100 today). Wider wheels/tires were a mistake on my part ( I knew better just hated the tires sticking so far in the fenders) that said your right subject closed on my side.

 

The only regret I have about my Heidts Mustang II kit for my 54, is that I used the stock style MII lower control arms, with the strut rods. Not only does it look worse, but my tires rub on them when I turn the wheel too sharp. However, that is the first new part my 54 is gettin this winter. Also, I do not believe those spacers on the rack make the suspension feel any heavier or wierd at all. I dont even notice them on there, but I felt it necessary to put them on.
I have talked to people that think the same thing about the MII being too light for our pickups, but the kits you get are designed for heavier applications, am I right? They are so much easier to put in than the other styles that I have seen, such as the Volare clips, Nova clips, and the LTD clips. These usually require cutting of your original frame and to me, is not worth it. To each their own, I have a friend that has put 3 volare clips under his 48,49, and 50 F1, and they seemed to be more hassle, but he did a nice job, not knocking those clips, but why cut up a perfectly good frame?

 

What is too light IMHO is the original control arms and the small MII brakes. Those parts were designed for a 2000# vehicle with a significantly lower front end weight of ~ 1200#. When those parts are put in a 4000# truck with a much higher F-R weight bias they are carrying 25-2700#, more than double their design weight. In order to carry that much weight, much stiffer springs must be used which puts a significantly higher shock load on the parts as well as the high static load.
The newer kits address these issues by replacing the stock control arms and mount points with tubular wishbones and adding 11" brakes.
With widening the cross member you must extend the INNER (fixed) portion of the rack the same amount so the pivot in the rack arms remains at the same position relative to the control arms to avoid bump steer problems. Just extending the outer portions will produce drunken monkey steering.
This is my fairly knowlegeble opinion, YMMV.