1935-1940 Ford Chassis Builders Guide
Did you know that this popular Ford Chassis chassis was installed in the 1940 Ford Coupe Build of the 2012 Street Rodder tour car? Sure was and it turned out awesome! Check it out!
Thank you for your interest in a Fatman Fabrication frame for your 1935-1940 Ford. Before you begin there are a few things we would like to discuss and point out.
First, PLAN YOUR PROJECT!!! Know how you want it to look when it's finished. This will be repeated many times because it cant be said enough. Do you intend for it to be hi-tech or old style? Billet wheels or painted steelies? Pro street? Pro touring? Ground scrapping low? Whos going to drive the car and where? Is it going to be a low mileage show car or a freeway flyer for cross country cruising? Establish parameters based on reality and not just wishful thinking. Blown big block motors rarely make good long distance cruisers. Big inch wheels look awesome on some cars but tradeoff ride comfort for looks by requiring short sidewalls that don’t absorb road shock. Remember, there is a tradeoff to everything, so save yourself time, money, and aggravation by planning your project.
Second, keep in mind you are building a car. You may be using an old steel body, but Henry was not very exact in the manufacturing process 60+ years ago and there are minor variations in all these old cars. There is some excellent quality glass bodies but each has its own variations and tradeoffs. Some are not even made to fit on a 1935-1940 frame. Not everything is exact and some minor modifications are likely on every step of the car, so plan for that and test fit everything before you paint or powdercoat anything. But, after building close to a thousand of these frames we have them dialed in pretty good and that includes our Ford Chassis.
All of our frames for the 1935-1940 Fords are constructed of 2x4x.188 mandrel bent rectangle tubing. They are made to follow the original shape and form, and to fit with original body mounts. We include radiator mount brackets, bumper mount holes, drill and tap the topside body mount and gas tank holes. Body boxes are also included. We have found that 60 year old and repro runningboards and fenders seldom fit together well without tweaking. We suggest you fit them, then drill and tap 5/16 fine thread bolt holes into our 3/16 thick frame rails in the proper location. Then the bolt holes will be where you need them, rather than having to stretch a hole in a fender to match a predrilled hole. We have been accused of building our frames too heavy duty, but we pride ourselves on a strong, rigid frame which youll find is an extra big benefit if youre using a fiberglass body or parts. And besides, why build anything on a questionable foundation?
Fatman frames come standard with Stage II suspension, which uses coil springs and stock MII shocks. The ride height is approximately 4in lower than stock height. Track width comes stock (56.5in) width which works well with normal street rod heights, as long as 6in front wheels with a centered, non-offset hub are used. If you want to run extra-low, use 7in or wider rims, or use traditional style offset wheels (such as original halibrands, 5-spoke Americans, or wire wheels), youll find that tire to fender clearance is very tight. Billet wheels, and some after-market wheels are available with special backspacing to increase tire clearance, but of course your wheel selection will be limited.
Another solution is Fatmans exclusive narrowed (54 ) option. By narrowing the mounting points for the control arms 1in per side, tire clearance is greatly improved so that extra-low ride height and full wheel selection can be accommodated. Narrowed frontends will require a frame notch and are only available on stage III coilovers or stage V shockwave.
If you want to run extra low, you can use drop spindles or our ultra-low option. The drop spindles are more expensive, and will reduce ground clearance. Our ultra-low option mounts the crossmember 1in higher in the frame. Chevy engines normally fit fine, but Ford engines are even harder to fit and arent recommended. The ultra-low option is usually used on 1935-1937's which sit higher off the frame than 1939-1940.
Stage III coilovers are our most popular option for the frontend because slight height adjustment, excellent shock, and good looks that match the polished stainless tubular control arms that is standard on all frames. QA1 coilovers with 12 way external shock adjustment are now standard on all Fatman frames.
Our Ford Chassis can come equipped with Air ride in either CoolRide (Stage IV) or Shockwave (Stage V). CoolRide has the air spring in place of the coil spring and the shock mounted behind the control arms. Shockwaves are similar to how a coilover looks and mounts with the shock inside the air spring. A compressor system is needed with both options. Another consideration with air ride is the brakes. Because the air springs are bigger in diameter, a caliper with the banjo bolt on the bottom instead of the side is needed. The Wilwood caliper option, complete Wilwood system or Baer brakes are recommended.
Manual rack and pinion steering is standard on roller frames, but power steering is available as an option and is generally recommended. The power steering option on narrowed front ends requires a special rack and is higher priced.
Shocks are probably the biggest factor in ride comfort and handling of a car. Shocks are the brains of the front suspension because it controls the velocity of the suspension. NASCAR teams take dozens of shocks to the track but only a couple pair of springs. Monroe gas charged shocks are standard on Stg II and Stg IV and do a good job, but Carerra and QA1 have adjustable shocks that we can provide that allow you to fine tune your ride comfort and handling of your car. Stg III and Stg V have the adjustable shocks standard.
Something to keep in mind as we discuss brakes is that some people use bigger brakes to fill their new big billet wheels or as a dress up, without thinking about the safety aspect. 1935-1940 Fords generally weigh about the same as a stock Mustang II car, but remember bigger brakes are better brakes. You have never heard anyone say if I had less brakes I could have really nailed that car.
That is why all Fatman Fabrication Ford Chassis & Frames come standard with ECI kits that use early GM big piston calipers and provide 65% more braking capacity than the stock Mustang II, and twice as much as other kits that that use the small piston GM calipers. These 11in disc brakes use OEM parts that are easily serviceable units using parts that are available at your local auto parts store, should you need to make emergency repairs. 5 lug 4.5in(Ford pattern) is standard. 5 lug 4.75in(Chevy Pattern, w/ 12mm x 1.5mm metric studs) is also available but use the above mentioned small piston GM calipers. Talk to the Fatman rep. about the options that are available for bigger brakes if using Chevy pattern.
We have several options from Wilwood. As mentioned earlier when talking about air ride we have to use the small piston GM caliper with the lower banjo bolt location to clear the air spring. Wilwood has an aluminum GM big piston replacement caliper with the banjo bolt in the proper location and still uses OEM brake pads. Complete Wilwood big brake kits are available that uses aluminum hubs, 4 piston aluminum black calipers with 11 inch, 12 inch, or 13 inch rotors. Drilled rotors and polished calipers are options on these kits.
Brake kits from Baer Brakes are also available. Keep in mind that larger brake kits require larger wheel/tire combinations. Talk to the Fatman rep about what will fit. Remember bigger brake options are cheaper than a new fender or grill that you will have to buy because a new Honda that you rear ended has better brakes than you! Above all, think safety first.
Master Cylinder and Power Brake options:
Manual brakes come standard and work well with common disc/drum combination brakes. They leave extra room for exhaust routing also. Power assist brakes are a great option and are recommended with disc/disc applications. To make it easier to service the master cylinder, remote filling kits are available as is a â¤œcoolerâ¤? looking aluminum reservoir kit. Chromed and polished booster/master cylinder kits are also available.
We use standard automotive steel brake lines for brake plumbing. These are D.O.T. approved, show quality looking and will last a lifetime. When you see the bent lines you will swear a machine did it. We also use braided stainless flex hoses from the frame to the calipers. Metering valves are used with disc/drum applications. 2 psi residual pressure valves are used between master cylinder and discs, and 10 psi residual pressure valves are used with drums.
We use Chassis Engineering parallel leaf springs on the rear of our Ford Chassis. They can be setup to accommodate either the standard or ultra-low ride heights as mentioned earlier. They provide excellent ride quality and adjust for changes in load (people, gas, and luggage) very well. They are excellent for stock width frame, but dont work well with frame rails that have been narrowed to accommodate larger tires. 4 link rear suspension (either parallel or tri-link) is used with coilovers or air ride. We often recommend the air ride on the rear due to the flexibility afforded with the variable pressure. Coilovers do not accommodate changes in load well as they have a given spring rate that may be comfortable in a empty car, not heavy enough in car loaded with extra stuff. The air ride can be set for a comfortable ride and proper ride height at the push of a button, regardless of the load. Dont forget a compressor fill kit is required with an air ride suspension so there is an extra cost and there is less exhaust routing area. On some cars the floor drops down below the top of the frame and will get into the 4 link bars, so sheet metal may have to be modified.
Rear sway bars come standard on all car frames to help control body lean. We seldom use a front sway bar because of the nearly 50/50 weight distribution and good roll center on Mustang II based suspensions. If using a big block motor then one is recommended. Also if you want a G machine that has excellent cornering qualities, then choose this option. Plus, if the mid-life crisis guy with the new Corvette thinks that your old car is no match for his, you will have something for him. Beware; some ride quality suffers to make it handle better. Again this all goes back to what kind of car you are building.
If using rear disc brakes with coilovers or air ride suspension with either disc or drum, a prostreet style rear sway is required.
Fatman Fabrication standard roller Ford Chassis & Frames include an 8in Ford rear. These are used rearends from Maverick and Granada passenger cars that have been sandblasted and primered. If you will take the time to rebuild the brakes, replace the axle bearings and seals, you will have a good serviceable rearend with a set of highway gears that will last for many trouble free miles, at minimal expense. We can rebuild brakes and replace bearings and seals if you wish.
9in rearends are available and are custom made to the proper width. You can get brand new gear sets in Trac Loc or open configuration. New drum brakes are also available for the 9in rear.
You can get disc brake conversions for both the 8in and 9in rearends. We generally use ECI kits that use O.E.M. parts. Kits from Wilwood are also available to match front brake assemblies or also for better frame clearance issues.
8in wide wheels, regardless of the diameter, will fit under the rear fenders with the proper backspacing. 10in or wider wheels will require the rear frame rails to be narrowed. We will have a 9in rearend made per your exact measurements of your mounted tire and wheel combination (No, we are not going to go by what the tire manufacture says the inflated tire size is. I have yet to see the right measurement in those pamphlets).
For the guys wanting to build a show car, a polished aluminum 9 inch or quick change rear should be considered.
First let me talk to you guys that want to run the 4.6 and 5.4 modular motors. They will barely fit between your fenders (about .25 inch clearance on either side) because the motor is so wide. The oil filter on some ends up where the upper control arm is, we have to cut up the x-member for exhaust clearance, and the brake pedal gets into the back of the motor just to name a few problems. Its like putting 3 lbs of stuff into a 2 lb bag. But if you just got to have it, be prepared for extra effort and cost.
The 35-39 Standard radiators lean back, creating fan clearance problems. The vertical 39 Deluxe-40 radiators leave more room and a small block Chevy with short water pump and small distributor doesnt require a recessed firewall. Any other motor combination or anything in a slant back radiator car will require a recessed firewall. Chevrolet small blocks fit the best and are easily customized and they fit better than anything else. The chart below will provide some help in determining a workable combination.
We can mount most any transmission whether Ford or Chevy. We will need the measurement from front of tranny to the transmount on the Chevy 4L60E as they do vary. With manual shift trannys we will need the measurement from front of bellhousing to transmount, the width at the widest point, and if you will use hydraulic or mechanical clutch linkage. The option price on clutch pedal setups does vary according to what setup you use, any frame rework, and if you want us to mount a clutch master cylinder.
All frames and Ford Chassis come completely assembled (except air ride compressor systems and fuel tanks) and sprayed with grey lacquer primer. As an option Reflections Paint and Body Shop, Inc. (located in the same complex) has a frame priming service that includes the following steps:
- Alcohol wash
- Orbital sanding
- Phosphoric acid wash
- Etch priming
- Epoxy priming
Epoxy primer is packaged in a variety of different colors. The black epoxy is the most popular of all the colors and does not require a topcoat when properly applied. When catalyzed and sprayed, the black epoxy gives the same satin appearance as any new sheet metal parts right out of the factory. This primer can be scuff sanded and topcoat painted if desired, but is not necessary. This paint system is recommended by the paint manufacturer and is the best undercoat system available on the market today. Remember, not everything is exact and some minor modifications are likely on every step of the car, so plan for that and test fit everything before you paint anything.
Before you move on, be sure that you have read the Builders Guide on our Ford Chassis. It does have a bunch of great information.