What is your opion of the Fatman's stub frame(Must II) for a 39 La Salle. Anyone even installed one in a late 30's big GM car? How did it drive?

Well over a dozen views and no responses ...

I believe that a big GM vehicle such as the LaSalle is to heavy for a Pinto/Mustang II suspension. The donor car is a good bit lighter in weight than the LaSalle. The wheelbase is a lot shorter. The original track width is more narrow. It was designed to be used with a 9 inch brake rotor.

Now I understand that some of these issues can be addressed and upgrades made ( like the brake rotor size ) ... but the factory engineered suspension design for a light weight disposable economy car has to be a concern ... at least to me. Go find a similar era vehicle ( mid 70's ... 74 to 78 ) with a comparable weight and wheelbase of the LaSalle ... and look at the A arms and suspension ... then compare them to a Pinto/Mustang II A arm and suspension. Vast difference ...

Deuce is exactly right....

Glad your on midnight shift Deuce

The aftermarket "Mustang II" suspensions are not built the same way as the original cars' were; they are MUCH beefier. They are referred to as "Mustang II" suspensions because they use the original design concepts and geometries. But if you put an original MII suspension side-by-side with an aftermarket suspension from Fat Man and the others, you'll see a HUGE difference. The aftermarket kits are also built to use large brake systems.

I would have no worries using one IF the manufacturer builds a kit specifically for your model.

Just make sure to read up on the posts in this forum on how to improve the aftermarket kits for better safety. And speak to the manufacturer about your application.

Hope this helps.

Antny

I have been to Fatmans shop many times ...

I stand by my statement ...

The wheelbase, tread width and weight issues should not be ignored. Aftermarket stuff is rarely as well engineered as Factory Ford, GM or Mopar stuff.



A 1939 LaSalle weighs at least 4500 to 5000 lbs with a late model engine/transmission. A vehicle this large ... needs something more substantial than a Pinto front end.

Just my nickel ...

As far as the MII track width - this is from the Fatmans site...

MII Kits
56½" Hub-to-Hub
58½" Hub-to-Hub
60½" Hub-to-Hub

As long as the Lasalle is within these specs I don't see any reason you would have a problem (other than it being Ford based technology...Doh!... )

MII "kits" are used in thousands of hot-rods and as someone already pointed out - this is not the MII parts out of a boneyard from a Pinto (nice picture BTW!)

You would, of course, want to use correct suspension components based on the weight of the target application - these being larger sway arm, springs that are made to handle the weight, bigger brakes.

But the other Fatman MII components themselves (a-arms, r&p) should be plenty beefy to handle the LaSalle - a quick phone call or email to one of the Fatmans engineers would really be warranted if you have any real concerns.

Fatman will build you a hub to hub stub to your specifications.just fill out their spec sheet with your measurements. I have one under my 36 LaSalle. The Current Fatman stuff is the strongest in the industry, If you want I can send you a picture of the hub to hub frame stub they built for me, then you can see for yourself, The current Fatman product is well built and nothing like any original factory pinto or MII unit. Deuce, that picture looks like a Cadillac Sixty Special ..

The different widths are just a widened crossmember ... the A arms are still the same short little length Ford designed for Pinto over 30 years ago.

Do you really believe that a Fatman sales person will tell you his product is not perfect for your project ??

A Pinto/Mustang II front end is great for 33 - 34 Ford or Chevrolet ... or similar weight vehicle.

A friend of mine worked for Brent ... for years. Failures are not publicized but I know of at least 5 suspension failures ... 2 with Pinto/Mustang and 3 with welded drop spindles. Thousands SOLD ... How many installed and on the road with thousands of miles ?

This is not meant to bag on Fatman ... just the Pinto/Mustang II based suspension under too heavy vehicles. Knew a fellow who put a Pinto/Mustang II under a 35 Buick. He used a Fatman kit. After a thousand or so miles ... the tires were wearing badly. He had it re-aligned. It was off a fair amount. After a thousand or so miles ... the tires were wearing badly again. He took it to the alignment shop ... it was off. The A arms were bending. He had already installed heavier coil springs to help hold up the 35 Buick and the 455/400 turbo he had installed. With all that much spring rate ... and the weight of the 35 Buick bent the Pinto/Mustang II A arms. His were original OEM Ford ones so he bought a set of aftermarket tubular ones ... 2 thousand miles and the same thing.

I have also heard of the lower bolt breaking ... so I copied this from another post on the Pinto/Mustang II IFS failures

http://www.hotrodders.com/forum/ifs...lts-127985.html

QUOTE ...

I had heard of bolts breaking, but it looks like this time the crossmember itself ripped apart.

Was that a Heidts Superride setup?



Or a TCI setup?





Both are big names in the MII kits.

The way the lower A arms mount below the crossmember on that triangular mount instead of through the crossmember looks like it is. There is an awful lot of stress on that little 4" width of metal, with no gussets to put some of the stress back into the crossmember..


It's a good thing no one was hurt.


Later, mikey
END OF QUOTE



Just my opinion ... everyone is entitled to their own. But you can only fool Mother Nature so long ...

[QUOTE=Deuce]The different widths are just a widened crossmember ... the A arms are still the same short little length Ford designed for Pinto over 30 years ago.

<SNIP>

Deuce makes some very good points regarding the weight of the vehicle, etc. (I didn't realize just how large that car is!). However, just to clarify the above statement; the a-arms in these aftermarket kits are NOT the same as the 30-year old stampings. They are much beefier tube-type a-arms. Using these in conjuction with strut rods should be fine for just about any passenger vehicle.

Give a call to Jim Meyer Racing, I'm sure they can design a custom (and safe) IFS for the LaSalle.

Antny

As it turns out ... Sixguns is correct ... the car is a Cadillac ... but was listed as a LaSalle in the photo listing. That is undersatndable because LaSalle and Cadillac were brother/sister type companies ... like Ford/Mercury or Rolls/Bentley

This is a 39 LaSalle ...



Not much difference really ... mainly front sheet metal ... still a very heavy ... long wheelbase upscale vehicle for 1939.





The LaSalle already has a IFS ... designed by Cadillac ...

Let me explain my position......The car belongs to a friend & he is asking me what options are available & what do I recommend?

He has limited knowledge about car suspension & want advice. Because of his limited skills (I will do the welding) I thought the Fatmans stub frame would be easier to set-up. He came to me asking about a frame swap, but intially I told him it's usually better to modify the stock frame. I am now wondering if it might turn out easier for him to do a frame swap, the La Salle has a 120" wheelbase. The 50-80's Impalla frame have a 119", but I think the track would be too wide.
It looks like a Camaro front clip might be the way to go, however I was looking for a easier out(my labor will be free).

I'd appreciate any further discussion.