"El Mongrel" '65 Formula S Restomod
Part 11
Ok, the drive train is done and were moving on to goal # 2 Make It Handle. This will cover all the suspension mods and a few body reinforcements I made to bring the already sporty factory Formula S handling up a couple of notches. Hopefully it will be competitive with newer offerings like the Mustangs, Cameros and Challengers.
Part of the Formula S package was suspension upgrades consisting of a 13/16 (by my measurement) front sway bar, 6 leaf HD rear springs, heavy duty shocks, wider 14 x 5.5 rims and newly developed Blue Streak tires. This was a nice handling set up for its day but modern shock and tire technology has come a long way since 1965 so improvement in those departments will be relatively easy. I kicked around ideas for a tire/rim package for a long time but ultimately made the decision not to go for big rims and the much better tires they would provide. This was mainly due to budget constraints but also to keep the car more in line with the period vibe I was trying to accomplish. The remaining mods were meant to tweak an already good working system not reengineer and/or replace the whole works.
Were going to start at the rear of the car and work our way forward. Most guys dream of upgrades in the power department no matter what engine they currently have between the fenders. Early As frankly just didnt come equipped from the factory to handle anything more stout than the 235 HP 4bbl 273. The trans, U joints and rear axle will soon show theyre weak points once some real power is applied. One of the first modifications I made was to replace the 7 ¼ rear axle with an 8 ¼ pulled from a 4 door 75 Valiant parts car. If taken from any A body this is a simple bolt in swap that will provide many benefits besides the much improved strength. First, you will find an A body 8 ¼ is roughly 1.5" narrower than a stock 7 ¼, which when combined with another simple mod, will allow you to make full use of all the space in the wheel wells for larger tires. Second, all 8 ¼ are large bolt pattern (same as the popular 73-76 A body disk brake swap). Third, that axle will come with larger drum brakes already installed (freebie!). Be sure to grab the U bolts and shock plates when you pull the axle as the 8 ¼ has larger 3 axle tubes (same as 8 ¾). It would also be a good idea to pull the driveshaft too. In fact, if your stock springs are sagging like a fully loaded diaper, grab the springs, hangers, shackles, axle, brakes and cables as one whole unit. It is much easier to remove and install as an assembly rather than in pieces. Plus if you got tires and rims you can roll it to where ever youre going.
Your probably wondering what that simple mod I mentioned is. It does require a little welding and is a bit more involved than simply bolting it on. All the parts are available through Mopar Performance and consist of new offset front spring hangers, offset rear shackles and spring pads which move the springs in approx 0.80 per side. The net result is the spring is moved inboard, so the outside edge of the spring is lined up with the inside edge of the wheel tub, opening the entire width of the wheel well for more tire. This lets you use cop car rims or any other 15 x 7 rim with 4 1/4" BS (pretty common). The offset front hanger brackets are Mopar PN P4120077, the shackles P4120075, and the spring pads P4120074. The only welding required is to attach the new spring pads to the axle as they will need to be moved inboard from the stock location the same amount as the shackle offset. Be aware that most aftermarket spring pads have a 1/2" hole for the locating pin on the spring and that is larger than stock. Find some that have smaller holes and save yourself the hassle of making bushings to take up the slop. The best way to remove the old spring pads (if you don't have a torch or plasma, if you do then maybe you can reuse your originals) is to cut them down the middle with a cutoff wheel or recip saw and then pry the halves back and forth until the welds break. Do one side at a time and you can use the remaining original spring pad to set your pinion angle for the new pad. The front hangers are set up for the larger 5/8" bolt of the super stock springs (1/2 stock) but that can be easily rectified with 5/8 poly bushings (99% yours will be shot anyway) and two new grade 8 bolts. When I did this to my Cuda I also replaced the rubber bushings that came with the offset shackles with poly bushings. An added benefit of the new hangers is that you can swap them side to side and flip them just like you can with stock hangers which raises the spring bolt holes 1" higher in the car. This will lower the rear of the car just the right amount without having to resort to dearched springs or lowering blocks. When you do this the bolt holes will be slightly off and the holes in the frame where the hanger mounts will need to be elongated. Yeah its a pain but can be done with a carbide bit or round file and elbow grease. Unless your going to go the full spring in the frame and mini tub route this is by far the easiest and quickest way to maximize the use of the available space in the stock wheel well. It was a lot of work but well worth every minute and bloody knuckle.
I don't know how to do links but if you go to moparmusclemagazine.com/techarticles/suspension there is a good article and pics that walk you through the install.
Pic 1: Offset shackles.
Pic 2: Spring to tire and tire to wheel well- inside and out, is right at 1". I might have squeezed a 255 in there on an 8" rim but didn't try.
Pic 3: Offset front spring hanger. Hard to tell much difference from stock but the hanger is moved in against the outer wall of the "frame rail". The nut for the spring eye bolt is welded to the hanger and a hole has to be put in the frame rail for clearance. Spring eye bolt is 1" higher (flipped bracket) than stock so the arse of the car will sit somewhat more than that amount lower. This pic looks like it was taken before swapping hangers side to side.
Pic 4: Wheels are $60 Pick-a-Part finds off a 4 door diplomat. Made by Western Wheel back....? Same dimensions as a cop car rim 15x7 with 4.25" back spacing. Tires 225-60-15 front 245-60-15 rear. No wheel rub to date.
