If you have been following the March ’57 convertible project, then you know this is no budget build. The likelihood of using stock drum brakes and a 10-bolt rearend were right up there with me wearing rhinestone jorts and vaping. Yes, this is a show car that needs to check all the boxes. However, a modern disc brake upgrade will also do wonders to improve your enjoyment on the street and track. A quickly changing traffic light is no longer a hair-raising experience. And the same can be said about the rearend, which was not only undersized from the factory but often equipped with an open differential and cringe-worthy 3.08 gears. I wouldn’t recommend trying to turn onto a busy road with either.
When we last left off with the March ’57 Chevy, Saints & Sinners Hot Rod Shop in Punta Gorda, Florida, converted the Chevrolet Performance LS7 to wet-sump oiling and added the March Performance pulley system. Now that North Port Auto Body was nearly finished with the Tri-Five’s floor, we were able to commandeer the Art Morrison Enterprises (AME) frame. Saints & Sinners dropped the LS7 and TCI Auto 6X transmission onto the AME chassis to mock everything up prior to powdercoating it. These are the last days before paint and final assembly, and we can’t wait! After that it will still need an interior, glass, and convertible top to complete the build, but those are minor speed bumps on this long and arduous journey.
With the AME chassis in hand, Saints & Sinners started assembling the brakes and rearend. The AME chassis came with a 9-inch solid axlehousing, spindles, and even stainless steel brake lines. To make the chassis fully operational, we’d need front and rear brake kits along with axles, bearings, and a centersection for the rear. A word of advice: if you are attempting this at home, purchase all this stuff directly from Art Morrison. Piecemealing it together can often lead to mistakes, as we experienced. Despite our limitations, Strange Engineering was happy to work with us in figuring out the axle length and bearing set we needed. We went with the S-series cast-iron centersection with 3.25 gears, S-trac posi, 1350-series yoke, and 35-spline alloy axles with axle bearings and 1/2-inch wheel studs. Between the grunt of the 427-cube engine and steep ratios of the six-speed auto, this combo should be ideal for performance and highway cruising.
For the brakes, we turned to Wilwood Engineering. We were spec’d a 12.88-inch, two-piece rotor with Forged Narrow Superlite 6R front and 4R rear calipers. A minimum of 17 inches in wheel diameter was needed to clear the six-piston front and four-piston rear calipers, which we were happy to accommodate. [Following the install, we’ll be using Wilwood’s template to measure for a custom set of wheels.] The rear brake kit required the “Big Ford New Style” to match the ends on AME’s 9-inch housing. An internal parking brake (drum style) makes this kit ideal for a street car. Each kit comes with everything you need for the radial mount brake setup, including the BP-10 compound pads and hardware.
Follow along as Saints & Sinners wraps up the chassis and driveline on the March ’57 Chevy convertible. Over the next few installments we’ll be showing some additional metal fabrication and moving on to the paint.
1. Wilwood set us up with the Superlite 6R front brake (PN 140-9919-R) and brake line kit (PN 220-8307) to match the aftermarket spindles on the AME chassis. The front brakes do the majority of the work, so we were pleased that six, 4-inch stainless steel pistons would carry the load. A total of 8.2 sq-in of brake pad apply friction to the slotted iron rotors, which measure 12.88 x 1.1 inches. The rotor material, diameter, and thickness all play a role in heat dissipation and fade resistance.
2. Here is the bare spindle as it comes from Art Morrison, along with the Wilwood bearing and washers that sit inside the hub as well as the nut that secures the hub to the spindle.
3. The wheel studs were installed first on the hub, torqued to 77 ft-lb, before the hub was bolted to the hat and stuffed with its bearings and grease. The aluminum hub and rotor hat are two nice features of the Wilwood brakes. Both cut down weight significantly over other designs, and since it is rotating weight it will greatly affect performance.
4. Mike Morgenthaler at Saints & Sinners bolted the rotor to the hat (through the back side) using red Loctite and 155 in-lb of torque. Wilwood says to use an alternating sequence.
5. The rotor/hub assembly slides over the spindle with another bearing sandwiched in-between.
6. The nut is torqued to the spindle and the dust cover is screwed on to seal the hub.
7. Hands down, the most difficult part of the operation is installing the calipers and caliper brackets. The caliper bracket needs to center the caliper on the rotor. Wilwood says to start with two 0.035-inch shims on each stud, and add 0.016-inch shims until aligned.
8. When centered properly, the rotor should spin freely without rubbing on the pads. Red Loctite is used to secure the bracket to the spindle once complete.
9. Mike screwed the braided stainless steel brake line to the caliper and the hardline supplied with the Art Morrison chassis. As you can see, it runs neatly through the frame (more on this later).
10. Moving on to the rearend. Here is the 9-inch housing from Art Morrison. You have to love the modularity of a 9-inch—you never have to worry about setting up the gears. The centersection simply slides right in.
11. The axle ends are the “Torino style,” also known as “Big Ford New Style.” The significance of this is in the bolt pattern for the caliper brackets, and in that it houses the largest bearing available. While it doesn’t offer complete independence like a full floater, it is the next best thing and in most cases you will never know the difference.
12. Strange provided us with an S-series nodular iron case assembly (PN PRF130) that is 8-10-percent stronger than Ford’s original design since it is reinforced in critical areas, has heavy-duty main caps, and larger Timken bearings and races. The machining, finish, and the mil-spec looking case it comes in scream high quality.
13. We chose the 1350 series chrome-moly yoke, 3.25:1 Standard gear, and 35-spline S-trac posi. Unlike a clutch-style posi, the 9310 steel helical pinion gears are maintenance free and offer much better torque bias. And the S-trac is ideal for any street car, regardless of whether you favor handling or drag racing.
14. The Strange centersection (aka third member) slid right on to the dowels, and bolted in place. No muss, no fuss. Since we are just mocking this up, Mike did not install the gasket and silicone at this time. That will be done after powdercoat, for final assembly. Now on to the axles and rear brakes …
15. The Strange 35-spline alloy axle package (PN P3502) features a modified 1550 premium steel forging that is induction hardened. The majority of the machining is completed prior to heat-treating the steel, and it is also given another round after final machining. The 35 splines are cut with a 30-degree pressure angle.
16. Like the front, the Wilwood Superlite 4R rear brake kit (PN 140-9219-R) utilizes a forged billet caliper for rigidity and weight savings. While the pad area is the same as the front, it uses four slightly smaller pistons to grab the same size rotor. The internal drum assembly for the parking brake is designed to bolt right up to the Big Ford New Style flange, which spaces the four bolts 3.562 inches across and 2.00 inches vertical. The kit has an axle offset of 2.5 inches.
17. The Wilwood parking brake assembly was installed first onto the axlehousing.
18. The axle (with the bearings pressed on) was slid through it and into the housing while sandwiching the retainer plate. Since this is a 9-inch, there are no C-clips to attach once the axle slides into the differential.
19. T-bolts secured the bearing retainer using a 3/8-inch socket on the nuts, which were tightened through the hole in the axle face. This is what secures the axles should it ever break, which is a much better solution than C-clip eliminators used on 12-bolts that are prone to leaking (especially with all the side-loading in street driving, autocross, and road racing).
20. Like the front, the rear uses a radial bracket that has to be spaced properly, which was (again) the hardest part of the operation. Wilwood says to start with one 0.035-inch shim on each stud. Assembling the rotors was exactly like the front, minus the hub. Red Loctite was used on the bolts that secure the rotor to the hat as well as the caliper bracket bolts.
21. Last, but not least, the braided stainless steel brake lines were attached to the hardlines on the chassis.
22. Here is a good look at the hard lines from Art Morrison, which came with all the junctions and brackets. You can see how it follows the line of the chassis nicely, and stays tucked securely out of the way.
23. The brakes lines actually go right through the frame in a few spots, which makes it pretty seamless.
24. To finish off the driveline, Saints & Sinners ordered a custom driveshaft locally to connect to the TCI Auto 6X transmission and Strange 1350 yoke. The TCI trans is based on the 4L80E, so it uses a 32-spline yoke just like a Turbo 400. Strange (among others) offers chrome-moly yokes, which you may need to purchase first to take measurements.