1970 GTO - 2" rear drop w/ Air Lift
 

One thing I've wanted to do with my '70 GTO since I bought it was drop the rear end a touch. I don't know for sure, but I believe the rear springs were stock replacements, while the front end had a pretty decent drop, giving the car a pretty strong rake. A secondary problem I wanted to solve was that the car had the somewhat inherent problem of not sitting level in the rear (DS was ~1/2" lower than the PS).

I decided to get the look I was after with BMR 2" drop springs (SP015R) and an Air Lift 1000 bag kit (60744). While I thought the 2" drop might be a bit much, I could of course compensate for this with the air bags, and level the car out as well. Install was straight forward as you'd expect, however note that you will need to buy smaller clamps for the heat shields; the ones provided are far too big for any passenger car exhaust. Nothing really special here, just thought I'd share my install in case anyone else is looking to accomplish the same. For reference, tires are 245/60/15 rear and 225/60/15 front.

http://forums.maxperformanceinc.com/...1352766988.jpg
http://forums.maxperformanceinc.com/...1352767001.jpg
http://forums.maxperformanceinc.com/...1352767007.jpg
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I mounted the air valve in a factory hole towards the rear of the frame rails. I would have liked to have used the factory location behind the plate, but I wanted the lines separated in order to adjust the bags individually:
http://forums.maxperformanceinc.com/...1352767082.jpg

Old vs. New springs/bags:
http://forums.maxperformanceinc.com/...1352768612.jpg


I thought I had a better before picture, but this is the only one that really shows the difference in ride height:

Before:
http://forums.maxperformanceinc.com/...1352767888.jpg

After (you can see the wheel well gap is now gone in the rear):
http://forums.maxperformanceinc.com/...1352767898.jpg

Measurements were taken at centre of wheel well opening to bottom edge of the trim.

Before:
DS=26", PS=26.5"

After @ MAX 35PSI:
DS=27.5", PS=28"

After @ MIN 5PSI:
DS=25.5", PS=25.75"

...it is apparent by the measurements that the springs were not the issue (which I didn't suspect anyways), so I will have to run slightly different pressures to level out the rear of the car. I expect after some driving the springs will settle a bit and it may drop a touch more, but time will tell. It's not a huge difference, but has given me the look and flexibility I was after :)

On the cheap, El Camino rear coil springs for '68-72 are shorter than normal stock height '68-72 A-body rear coils.

thats interesting, why did they make the elcs shorter i would have thought it would be the other way around. :confused:

Elco's of that era had factory airshocks. Believe that disappeared for '73 models...might have been a rare factory option on '73+, but I never saw them.

Good info, any idea how much difference there is? I considered the 1" drop BMR springs, but didn't want to take a chance on it not getting me where I wanted to be (which they likely wouldn't have considering the 2" drop springs only lowered the rear ~1/2" thus far). I was leary of this as I used 1.5" drop springs on my Monte several years ago and it didn't drop at all (although the springs that were in the car had surely sagged somewhat). The other issue was the car not sitting level from side to side, which was the main reason for deciding to go with air bags.

Did either of you guys see the show muscle cars on power block last week when the guy they had on siad he had 1 of 2 Judges that were orbit orange???? When he said that all I could do was laugh. I don't know where he got his info but The car was just a Judge with the std. engine the Ram Air III, not a IV. It was the guy who also had a sublime lime Road Runner with a 440 six-pac. His judge was nice but where he got hois info , someone was trying to feed him a big line of DODO.:jumping:

Nice undercarriage. :)

thats true i didnt think about that.

Thanks! I didn't build it, but I do my best to keep as clean as possible. Wiping down the undercarriage isn't fun, but I only do it once at the end of each season and it cleans up pretty easy with the gloss finish.

85SS- your car is sweeeet! Thanks for that info also. I'm going to try the bags. I see you made a heat shield.

nice work.......suspected the same after installing new coils on my car.I ended up adding an extra spring insulator ( or just the outer portion of one so it could lay flat with the other) to one of my rear coil springs to level rear of my goat.

I like the stance, looks good! My 70 convert doesn't sit level, I have a big spring spacer on one side to level it out a bit, but it's still off. I might have to give this set up a try. did you notice any ride difference? May I ask what this set up cost? Thanks for the info.

Sorry for the late reply guys - I didn't get the reply notifications and haven't been on in a while (the little one in my profile pic keeps me pretty occupied :) ).

JimChevy - the Air Lift kit actually comes with the heat shields. The clamps they give you are far too big though; I bought some smaller stainless clamps.

pggto - I only had it out for a couple quick rides afterwards; it seemed to ride firmer with less body roll, but not overly stiff or harsh. Springs were $130 and the Air Lift kit was $88.