Jump to content

IFS swap 1948 p15 de luxe


mark888

Recommended Posts

Welcome aboard the best mopar forum around...........why do you want to swap out the original front suspension?................they can be made to work quite well........rebuild the suspension bushes and kingpins then get some new coil springs made, maybe 2" lower, get the upper shock mount changed to a solid mount on the chassis and maybe also get a thicker front swap bar made.......also throw a disc brake kit in there and you'll be able to go hunt some Frods & Chebolays........lol...........swapping out the stock style IFS is a much more involved proceedure than doing it on a car with straight chassis rails as our mopars have all the spring pocket stampings and much heavier front crossmember that'll get in the way..............I've seen pics of some done but unless you have fairly strong modifying & fabrication skills I'd think twice...........btw my Oz 1940 Dodge with the stock style IFS has a thicker sway bar, lowered/thicker springs & disc brakes and handles reasonably well and has done so since I built it in the 1970's.........my Oz 2 cents worth, regards, Andy Douglas 

  • Like 2
Link to comment
Share on other sites

It came from the factory with an independent front suspension. You need to be more specific about what it is you hope to gain from any suspension updates. You may not have to spend as much money as you think.

Link to comment
Share on other sites

If you want to lower it, remount the lower spring pockets to the bottom of the lower A arms. Mopar used the same basic front end setup from about 1936 till they went to torsion bars with unibodys in 1960.  I think they pretty much got the bugs worked out.  As mentioned there are some tweaks you can do but a swap to something like mustang II is going backward in my opinion.  If you want to clip it an early Dakota is an upgrade, but then you need to re fabricate front sheet metal mounting points and systems.  Take a close look at what you have and understand what you have before you get the saw all and flame wrench out.

Link to comment
Share on other sites

Why would you want to replace one of the better independent front suspensions ever designed and manufactured for something worse ?

 

Better sway bars, possibly better shock absorbers and perhaps an equal length tie rod system is all anyone would need.      All I have ever needed in over 50 years of driving these cars is that all components are in good shape and the alignment is on specs.   These cars are Chrysler's products and for their time were superior.  They are still good today.

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

10 minutes ago, dpollo said:

Why would you want to replace one of the better independent front suspensions ever designed and manufactured for something worse ?

 

Better sway bars, possibly better shock absorbers and perhaps an equal length tie rod system is all anyone would need.      All I have ever needed in over 50 years of driving these cars is that all components are in good shape and the alignment is on specs.   These cars are Chrysler's products and for their time were superior.  They are still good today.

I could not agree more Dave, when I owned my 47 Chrysler, fantastic IFS stock,  the added benefit would be a shock relocation but really that's it.

Anti-sway bars front and rear, this set-up was well ahead of its time.

Sub frame IFS clip Phooey...

Even my truck with I beam, is not bad, is a truck, but all in good shape rides and handles darn good, nothing like the Mopar cars though..

Link to comment
Share on other sites

so I was considering doing a swap because of some rust holes on the k member.  I thought it would be easier just to find a good kit. I was also considering doing air bag suspension as it went over very well on a 1951 chevy truck i built a few years back

Link to comment
Share on other sites

25 minutes ago, mark888 said:

so I was considering doing a swap because of some rust holes on the k member.  I thought it would be easier just to find a good kit. I was also considering doing air bag suspension as it went over very well on a 1951 chevy truck i built a few years back

It would be a lot simpler to just cut a "U" shaped section out of the bottom of the K-Member,blast,clean,and coat the inside,and then weld in a donor section to replace it,or just make a new one that fits.

Link to comment
Share on other sites

Mark...........how bad is the rust?.........I will agree that the front crossmember or is this the "K" member you refer to does sometimes get rusted out in places due to its design but how much rust is there?...........also I suppose it comes down to what sort of car you want to have, if you want to lay frame which is the current thing then you'll have your work cut out for you as it will be difficult to get the original style front end down that low, but with some thinking and planning you should be able to drop the static height of the car at least 3-4 inches, maybe more..................anyway as I asked, how bad is the rust in the chassis?...............also GregG's suggestion regarding the spring pocket mounting is a good suggestion and I forgot about dropped spindles which can also add another couple of inches to the drop........maybe up to 5-6 inches down in total.............Andy Douglas    

Link to comment
Share on other sites

I'm not advocating either path but I have both.  My 47 has a GM front clip and my 49 has a factory IFS.  Here are a few of the PROS to adding a modern suspension:

1. Going from king pins to ball joints ++++++

2. Power steering if you want without the kludge of a Cavalier R&P

3. Better Geometry for highway use (ability to have more caster and split, anti dive characteristics......)  

4. Getting the steering box out of the engine compartment (engine swaps)

5. You can set your vehicle ride height to exactly where you want it with the control arms riding in the stock position

6. Correct wheel position (centered in fender)  Not all vehicles have this issue

 

CONS of a clip, PROS for keeping stock setup:

1. If you don't know what you are doing you will ruin your frame.  This is not for the novice or faint of heart.  I've seen some SCARY clip jobs...

2. Don't underestimate the amount of fabrication involved.  Clips could end a lot of projects prematurely. Don't believe the hot rod shows on TV that make this stuff look easy, it isn't.

3. The stock front suspension is pretty darn good, especially after adding disc brakes and shock mount mod.

4. You can add power steering (a lot of sacrifices doing so). I am biased here cause I hate R&P steering.  These aren't sports cars

5. Some locations that do annual vehicle inspections will balk at these type of modifications.

6. Track width of some clips is too wide.  I had to install Fatman narrow control arms on my 71 Camaro clip in my 47 = $$$$.

 

If you do change the suspension, I agree with using a Dakota or GM over the Mustang II.  Either way you're going to have to lop the frame rails off at the firewall so why would you put a Pinto front end in with R&P?

 

FWIW (free opinions are worth what you paid for)

Adam

 

Edited by Adam H P15 D30
  • Thanks 2
Link to comment
Share on other sites

Well Mark, you get the "gist" of mostly the resto guys.

Adam nicely listed the "pros and cons".

Unless I missed it, no one listed "the journey".  If you're not a resto guy, patching in an alternate IFS can be fun project, 'tho not an easy one for a beginner. 

I WAS a beginner!  I faced the same issue and considered a purpose designed clip from Fatman vs. and IRS crossmember from Heidts or Kugel.  With lots of measuring and stressing I installed a Kugel Komponents IFS cross member and couldn't be happier with the Wilwood brakes, R & P steering and adjustable ride hight.  After 35K miles I feel I made the right decision and I are now "experienced",....to some degree.

-

Img_5497.jpg~original

IMG_1301_zps3669b60e.jpg

Link to comment
Share on other sites

3 hours ago, Adam H P15 D30 said:

 

 

6. Track width of some clips is too wide.  I had to install Fatman narrow control arms on my 71 Camaro clip in my 47 = $$$$.

 

 

Adam,my 48 P-15 has a 76 Camaro frame clip,and everything attached to it is stock Camaro. I don't know/generally don't care a whole lot about Camaros,but I was thinking the 71's and 76's were the same because the body shell seems to be the same? Obviously they weren't or you wouldn't have had this problem.  BTW,mine still has the 305 and piece of crap Turbo 250 that was in the 76 Camaro in it. Think maybe the donor car you used was a hi-po version and that's why the control arms were different?

 

BTW,mine was pretty much the same width as the P-15 chassis,and the front and rear tires  on stock Camaro Rally wheels are centered perfectly in the wheel wells. It also has the stock 76 10 bolt GM rear from the same donor car.

Edited by knuckleharley
Link to comment
Share on other sites

Track width on my clip was about 3" wider than stock.  I suppose I could've made up the difference with wheel offset....  I am also not sure if GM made different width Gen 2 Camaro clips but I don't think so.

 

Centering in the wheel well is a function of careful measuring before cutting.  I did my initial cuts and welding with the body in place, removed the body later to finish the job so my fenders were on it when I set the clip in place.  Not sure if this makes sense or not?

 

Adam

Edited by Adam H P15 D30
Link to comment
Share on other sites

Here is what it looked like with the stock control arms in place.  

Note: Not factory GM wheels

post-6454-13585361766759_thumb.jpg

 

Narrow control arms

post-6454-13585367677471_thumb.jpg

Hard to tell but I gained about an inch on each side.  

 

post-6454-13585367670729_thumb.jpg

Since the O.P. asked for any help, here it is after finishing the welding.

 

post-6454-13585367679743_thumb.jpgpost-6454-13585367681818_thumb.jpg

 

Radiator support mod.

 

post-2787-0-48659500-1397355587_thumb.jpgpost-2787-0-10500700-1397180258_thumb.jpg

Narrow arms installed

 

Like I said earlier, it is a fair amount of work and lots of planning in advance.  

@knuckleharley Do you have pictures of yours?  I would love to see how you did it with essentially the same clip.  Thanks

Edited by Adam H P15 D30
Link to comment
Share on other sites

From personal experience I am not a fan of the Fatman/Heidts style Mustang II kits.  This style of kit uses a single 1/2" bolt as the pivot for the lower control arm.  I put a Fatman kit in my 1970 Mercedes when I installed the Ford 4.6L V8.  At about 50,000 miles the lower control arm bolt on the right side sheared off where it exited the back of the cross member.  My wife was driving the car when it happened, fortunately she was close to home and only driving about 20mph when she went to stop for a traffic light, heard a "bang" and the car dove to the right.  The lower control arm bent but did not come loose so the car didn't fall to the ground.  When I pulled the broken end of the bolt out of the lower control arm you could see a vertical strip of fresh break about 1/16" of an inch wide, the rest of the cross section of the bolt was corroded.  This is classic fatigue failure, a month before the bolt broke we had driven the care from Portland to Reno for vacation at highway speeds, through the mountains.  I know the bolt was seriously compromised during that trip and had it broken at 60mph on a mountain curve I probably wouldn't be writing this now.  It's been 2 years and 10,000 miles since that incident and I recently pulled a bolt for inspection, it is showing signs of fatigue cracking at the same location it broke the last time.  mrewstory, at 35,000 mile I strongly recommend you inspect the lower control arm bolts, or just replace them.  If you can get them out, mine were corroded in place and it took two days, $100 worth of drill bits and two 1/2 inch drills to get them out.

 

I will not use another one of those kits on any car I build.

Link to comment
Share on other sites

3 hours ago, Adam H P15 D30 said:

Track width on my clip was about 3" wider than stock.  I suppose I could've made up the difference with wheel offset....  I am also not sure if GM made different width Gen 2 Camaro clips but I don't think so.

 

Centering in the wheel well is a function of careful measuring before cutting.  I did my initial cuts and welding with the body in place, removed the body later to finish the job so my fenders were on it when I set the clip in place.  Not sure if this makes sense or not?

 

Adam

I was talking about  the width of the Camaro frame clip,and the width of the P-15 Frame,and yes,your centered wheel explanation makes perfect sense/

Link to comment
Share on other sites

3 hours ago, Adam H P15 D30 said:

Here is what it looked like with the stock control arms in place.  

Note: Not factory GM wheels

post-6454-13585361766759_thumb.jpg

 

Narrow control arms

post-6454-13585367677471_thumb.jpg

Hard to tell but I gained about an inch on each side.  

 

post-6454-13585367670729_thumb.jpg

Since the O.P. asked for any help, here it is after finishing the welding.

 

post-6454-13585367679743_thumb.jpgpost-6454-13585367681818_thumb.jpg

 

Radiator support mod.

 

post-2787-0-48659500-1397355587_thumb.jpgpost-2787-0-10500700-1397180258_thumb.jpg

Narrow arms installed

 

Like I said earlier, it is a fair amount of work and lots of planning in advance.  

@knuckleharley Do you have pictures of yours?  I would love to see how you did it with essentially the same clip.  Thanks

No photos. It was already done when I bought it,but the car has to come apart for a total redo soon,and I will take both before and after photos  of the process. It was half-assed when I got the car. The engineering was good,but at places it was just tackwelded with no reinforcement plates.  In fact,there was only one bolt in one motor mount and gravity holding the engine and trans in the car.  The trans was just sitting on L brackets on each side. No holes in the brackets to even put a bolt though. I was shocked at what I saw when I got it up on a lift so I could take a good look. Still,I drove it and enjoyed it for a couple of years before the engine backfired and caught fire under the hood The 305 had low oil pressure when warmed up,and the trans was junk. Replacing them with a balanced and blueprinted 412 small block and 700R4 or Turbo 400,and I'm damn sure going to recess the firewall so it's not like riding in a sauna in the summer.

VERY pretty paint job with faded flames that was put on over surface rust that is popping out all over,etc,etc,etc.

Still,I got it so cheap I can't complain. It owes me nothing.

  • Thanks 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Terms of Use