Ive been reading so much conflicting info on keeping the factory boxed control arms, factory rear sway bar, f41 braces etc VS basically going all aftermarket. Are these after market pieces (UMI for example) really worth the money? or are you just as good running what was designed 40 yrs ago? The car build I have in mind will see track time and be atleast 500hp, but will also be on the street if that helps.
Nothing wrong with the boxed factory lower pieces. Might want to consider buying a set of adjustable uppers. That would be my only change. Be sure the bushings are good on all pieces. Mike D.
stock stuff is ok as long as its in good shape you can box the uppers and lowers yourself if you have welder and some metal ,rubber bushings are fine back there to
Frame off restoration of my '70 GS Stage 1, includes all UMI Performance suspension parts, for improved performance over original suspension components: 2103 1964-1970 GM A-body tie rod sleeves 403133-3 Upper & Lower tubular A-arms, taller upper & lower ball joints 403534 Front & Rear anti-sway bars 4028 1968-1972 GM A-body rear control arm reinforcements/frame braces 4036 Rear upper control arms, non-adjustable with poly bushings & roto-joints (allows hard launch & cornering,without binding) 4041 Rear lower boxed control arms, non-adjustable with poly bushings & roto-joints 1" front lowering springs (small block springs for big block engine, for better launch & ride) 3" rear lowering springs (for lowered & leveled ride height, with no tire rub issues) KYB adjustable shocks JMHO, I don't believe there's an equal comparison from 40 year old parts to modern technology (materials, durability, performance, etc.), so I prefer to use higher standards of parts, than depend on "old" parts that "may or may not" stay together under hard driving conditions, when it comes to my BUICKS! You can use whatever you'd like; I only hope not to hear of any unfortunate malfunctions of your 40 year old parts, after you get your car built the way you'd like. I'm not suggesting that you need to build your suspension identical to mine, as you can improve only what you think may be necessary to help your own car handle better, not necessarily everything at once. For example, I'd recommend the UMI rear boxed control arms, in place of factory F41 control arms, just for the improved strength & handling performance! If you're only doing 1/4 mile, go with the dual poly bushings for hard straight-line launches. If you'll be doing cornering/slalom/autocross, you may want to consider the dual roto-joints, to prevent suspension bind. I chose to go for something in-between, as poly & roto-joint, for the best of both worlds; hard 455 Stage 1 launches for the 1/4 mile runs, and hard cornering on exit ramps for street driving (not a track car, ever!). So, just keep open to options, as it doesn't have to be one way OR the the other; you can combine both, factory AND aftermarket parts, as you need them to work together, for whatever purpose that you may choose, as long as you research which parts suit which needs best! Good Luck, and keep us posted with your project!
Also look into a HR hardparts bar on the rear to keep the car from rolling to one side when you launch at the track.
Spohn Performance @ spohnperformance.net has a flurry of suspension products. I have their rear heat formed solid rear sway bar setup, and it is outstanding!!! Comes as either a Pro Touring, or Anit-Roll Drag Bar setup. Upper and lower bars are available in a few choices too.
Nothing incorrect with the encased manufacturer reduced items. Might want to consider purchasing a set of flexible uppers. That would be my only modify. Be sure the bushings are excellent on all items. . . . . . . .
