I've been trying to ignore the voices in my head saying "what about traction, what about handling" during my driveline upgrades. They're really starting to get to me now...grrrr...

1970 Cutlass S, upgrading to around 475ish HP BBO, Tremec 5 speed and 8.5" posi with 3.73 gears. Front disc brakes from what I believe was a 1969 442, stock drum brakes. Front rims currently 14" with 15" on the back, 255/60R15 rubber on the back (that can be changed). I don't know if any suspension work has been done in the past apart from the front brake swap, but everything is at least 25 years old. It seemed to drive alright during my limited wheel time, but with the spongy brakes I really didn't put anything to the test. I can't find many photos of it from the side, but kind of looks like the rear end might be sitting a little low...or at least a little lower than I'd like. (Engine/trans are removed so I can't get a good sense of stance now)

It has a stock rear anti-sway bar (7/8"?) and boxed control arms.

This will be a street car, not likely to see the track at all. "Spirited" driving and I'm sure the occasional hard launch.

From what I'm reading and thinking, rebuilding front and rear suspensions would be a really smart thing to do at this point - new bushings, tie rods, etc. But what about springs? Car seems to sit ok. Would a bigger rear antisway bar make a big difference, or just be more of a nice to have? What are the advantages of tubular or other after market control arms, and would they really be worth the expense at this point?

I have a complete upgrade kit of Wilwood front discs - are they worth swapping in, or will the current stock ones suit just fine?

Long and short...what will I quickly regret if I don't address or upgrade now? I need to be budget concious, but still interested in sensible bang for the buck upgrades too.

 

I would start with brakes and suspension first. Front/rear springs and tire sizes can be done later. Forget the Wilwood stuff, do you really want a headache ? The front Disc brakes should work very well for you.
......Just my two cents worth.

 

I agree.

Changing rear springs is super simple.
Changing front springs is a bit more involved, but having the weight of the engine is a benefit.

The factory brakes in good condition with premium friction material should stop well.