Ok, so i'm plannin ahead before i go all out and buy a crate motor. I plan on ordering a ZZ 383 with 425 hp and i have a feeling im going to need to upgrade the rear suspension to compensate for all the extra hp. Does anyone know what i need to be upgrading, (im guessing the rear control arms for sure). Also, i have heard a lot of arguments over choosing between a th350 or th400 turbo tranny... any opinions?
Rear Suspension Upgrade
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TH400 is what would have been in your 72 if it was an automatic. It's a stronger unit then the 350 but both are good. I'd the 400 if you have it. Change out the 2nd gear drum and used a 32? element sprag to beef it up along with all the standard upgrades.
Your trailing arms are fine as long as the bearings are good. I use rubber bushings in the rear suspension parts.
The diff can be built better as well. Look above in the sticky posts for a lot of diff info on rebuilding them. If your're going to get on it then I would polish and tune the diff, use a solid sleeve, and steel cap. If you're not going to beat on the car too much then you can forget the steel cap and sleeve but still pollish and tune the posi.
Your trailing arms are fine as long as the bearings are good. I use rubber bushings in the rear suspension parts.
The diff can be built better as well. Look above in the sticky posts for a lot of diff info on rebuilding them. If your're going to get on it then I would polish and tune the diff, use a solid sleeve, and steel cap. If you're not going to beat on the car too much then you can forget the steel cap and sleeve but still pollish and tune the posi.
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I know what you are all thinking BUT...If it was me I would make sure all your bushings and u-joints were good and probably upgrade my shocks and springs.....
...redvetracr
...redvetracr
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Depending on their age, change all of the shocks and springs anyway....just for good measure. Especially if you have not had the car since the last replacement......I learned the hard way.
:agree: Take some time and think about what you want to do. Bushings, ball joints and tie rod ends should be changed if original and high milage, that will need to be done no matter what you want to do with it. Spring and sway bar and shock selection will depend on what you want to do with the car. Then there is Steeroids, transverse springs, all kinds of things.
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LOTS of things to consider before you start blowing your wad 
What kind of driving are you going to be doing? Street only, street and strip, street and track, etc. Are gasoline costs going to be a factor in driving the car? If you stay with an auto you don't have to worry too much about the rear suspension (as long as everything that is worn out is replaced). An auto is much less abusive of parts than a stick. A Turbo 400 is nearly indestructible. The newer autos will give you an OD gear so you'll get better mileage. I would think about my uses for the car long before plunking down cash for an engine and replacing parts willy-nilly.
Dep
What kind of driving are you going to be doing? Street only, street and strip, street and track, etc. Are gasoline costs going to be a factor in driving the car? If you stay with an auto you don't have to worry too much about the rear suspension (as long as everything that is worn out is replaced). An auto is much less abusive of parts than a stick. A Turbo 400 is nearly indestructible. The newer autos will give you an OD gear so you'll get better mileage. I would think about my uses for the car long before plunking down cash for an engine and replacing parts willy-nilly.
Dep
i knew it will probably take some time, so im just going to start getting the parts i need. the car is a daily driver, but i want some more hp because i bring it to a local drag strip. nothing major, just a little more umph behind the throttle.
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Before dropping a bundle into a new engine, you might want to consider a different rear end gear. It can make a MAJOR performance gain for not all that much $$$. If you are running a 3.08 cruiser gear, a switch to a 3.73 or 3.91 will make a noticeable difference.
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:agree: 3.73 is probably the best choice for mixed usage. Keep in mind, this will also decrease milage. I kinda lean toward 3.73 with OD tranny, and 3.55 without.
Speed=Money. How fast do you want to go?
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:laughing: ...no seriously...how fast do you want to go?
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Where??????
:laughing: :rolling: :rolling: :rolling: :rolling:
I'm geared for 196 MPH at 5800 in 6th with 28" tall tires... :lookinup:
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Pick one.
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