Previous Generation vs ours - Suspension

1964-72 vs 1973-77 A-Body Information

First off the poor geometry on the 1972 and earlier cars is in the front end. These parts will most definitely not interchange as they have different locating points on the frame. The upper arms specifically are much wider across the bushings and the center to center distance for the studs is correspondingly longer also. The spindles will work with a few mods which is the way to correct the front geometry on the early A bodies. To make them fit you either need a set of ball joints with the lowers turned down to fit in the early lower control arm or have the spindles reamed for the earlier B.J.'s.

As far as rear arms go, I'm not sure they would work as I think they sit at different angles. You would have to take a few measurements as to bushing center to center, bushing width, and bolt diameter. If I'm correct about the arms sitting at different angles, then the rear sway bar will not fit. The front will work with some work but that's a whole other thread.

Here's what I know about the 1964-72 "A"-Body chassis, and this is from first- hand experience this time since Grace is a 71 Cutlass (no more coil case ground stories here.....)

1) The "A"-Body frame is more desirable than the 1973 - 77 frame in classes where you would have to use the stock lower control arms and could replace the upper control arms with tubular arms and relocated upper mounts, such as an IMCA-style modified. These cars use the frame to just in front of where the lower control arms for the rear suspension would be mounted. The 1973-77's are wider, but are heavier and people would rather have light weight than the extra width (which is desirable in itself). There's a company in Walker, Missouri (Dirt Works) that builds an IMCA Modified chassis with the "A"-Body frames. Now some are now beginning to build Modifieds with the "Metric" "A/G"-Body frames, but most contend these are "throw-away" cars, ones that are junked after significant damage, where an older frame would be repaired. There are always the odd-ball frame combinations out there (we had one that was made from a 1973 Impala frame!) but this is the typical situation around here.

2) Although I'd agree with the facts that the 1970-72 disc brake spindles are getting too hard to find, the fact that they are two-piece is more of an asset in our applications. In our situation, we could replace the arm with a different one for Ackerman adjustment. Before they allowed aftermarket spindles, the ones to use were from a 1968-69 Catalina with disc brakes. These also had a replaceable steering arm, and a higher spindle level effectively lowering the car's front end. The 1973-77 "A"-Body spindles are not adjustable for Ackerman due to their one-piece construction.

For those who don't know what Ackerman is, it's the difference that one wheel turns in respect to the other. Believe me, people spend a lot of time adjusting Ackerman on their cars here, Lakeside Speedway (1/2 mile asphalt oval) is known for demanding that the car's suspension be set up as close to ideal as possible for the best lap times.

I'll be able to answer more questions about the front suspension after we get Grace done and get out to the track for some real-time testing. Against the cookie-cutter late-model Monte's, T-Birds and GP's we'll really stand out!

We have some in-progress pictures posted online, go to http://members.aol.com/ks7racing/index.htm and click on the Picture Archive icon in the imagemap for more info on what we're doing.

The 1973-up A-body cars use ball joints with different tapers than those on the 1964-72 cars. In fact, GM went to a common ball joint size, with the 1970-81 F-body, the 1973-up A/G body, and the 1977-up B-body cars all using the same ball joints top and bottom.

The calipers will interchange onto a 1969-72 A-body, but that's about it.

A 1968-1972 rear anti-roll bar mounts between the rear lower control arms, the bolts go in horizontally.

A 1973-1977 rear anti-roll bar mounts more or less under the rear lower control arms, rather than in between them. The bolt holes point upwards, rather than sideways.

I'm fairly sure the stock 1972 and 1973 sway bars don't interchange. I know that they mount differently, but I've read that you can use the 73 bar on the 1972 if you use 1973 control arms on the 1972. I saw this in Car Craft, and I've never matched this up myself, so I could be wrong.
[ Thanks to Mike Bloomer, Ken Snyder, Joe Padavano, John Carri, Donovan DrkSole96@aol.com for this information. ]