Need Suspension advice on street cruiser/bruiser 1967 Cutlass with some mods

[battenheaded67cutlass]

Hello All, this is my first thread, and I am only posting after reading a ton on here to learn all I can, but I have come to a fork in the road....



Trying to decide which way to go on the suspension setup..... This is going to be a shared car between my 70 year old Retired and disabled Dad and myself.... it has been a long project coming, and finally getting some "traction". I plan on street driving it in the mountains ( I live on the west side of Denver), taking it to cruises, and maybe down the dragstrip a few times if it runs really well.... Altitude really knocks the beans out of the Horsepower!

We really have no plans currently to do anything buy maybe try autocross, and that isn't for sure, because we are on a pretty tight budget and probably won't buy but one set of tires.... So I have to make them count when I buy them!





Specs on the car:

1967 Olds Cutlass 2 dr hdtp.

455 Oldsmobile - Motec M4 fuel injected engine built by Joe Mondello with Hydraulic roller cam (235 @ .050 on both) and fully ported Iron Batten Heads -9.5:1 comp. I think it will hit ~525 hp

American Racing headers 1 7/8 primaries and 3 inch merge collector - Thanks to these guys, they welded on my custom Batten port flanges

Built TH400 with 2800 stall TCI converter

3.73 12 bolt chevelle rear differential -no c clips Mark Williams axles, Eaton Truetrac, 3.73 Motive perf gears, moser 7900FM housing ends

ZL1 camaro Rotors front and rear, CTS-V 6 piston/4 piston calipers - LSX concepts caliper adapter brackets on the front and FLYNBYE rear caliper adapters

Probably use Corvette 18 inch wheels and billet spacers to get clearance past the big brakes..... but these haven't been purchased yet... really want 18's instead of 19's or 20's... Wanting to do 295/45R18's on the rear....


on the rear, adjustable upper control arms and fully boxed lower arms, with poly bushings on one end and the spherical delrin joints on the other ends





So, for the front suspension, here is what I have already or plan on doing:


I am looking at BMR 2 inch drop rears and 1 inch drop front springs(only one inch drop in the front because the 1/2 taller lower ball joints drop the height .5 inch, and the 700lb engine will drop it another 1/3 to 1/2 according to BMR)

planning on Tall lower ball joints

looking at Stock lower control arms with poly bushings installed (does someone make greasable ones?)

have 1.25 front sway bar with poly bushings
1 inch rear sway bar bolt on
Stock A body disc brake spindles





HERE ARE THE OPTIONS I AM LOOKING AT:

option 1- Stock Upper and Lower control arms with Poly bushings installed and tall lower ball joints only , All 4 Bilstein HPS 1000 Shocks or QA1 non-adjustable shocks

option 2 - Stock upper and lower Control Arms with Poly bushings and tall lower ball joint, with QA1 single adjustable shocks all around

option 3 - SPC adjustable upper control arms with extra tall ball joint and Stock lower Control arms with Poly bushings and tall lower ball joint, with Bilstein HPS 1000 shocks or QA1 non-adjustables - there isn't money for both SPC's and adjustable shocks.




The question is, with the suspension being tight and rebuilt on poly bushings, with big 18 inch tires, and being lowered, will a novice, non-road racer like myself really notice a substantial difference in using the SPC upper control arms?

I am wondering if option 2 would be the best overall for us with those BMR lowering springs... with the single adjustable shocks, will these make the most difference?


Also, I have never ran lowering springs on stock control arms, will the alignment be tough to do?

We only have so much to spend on what is left on the car, and although I would love to do the SPC arms and adjustable shocks, we just don't have the budget.... same for forged 18 inch wheels.... thus the reason for the corvette replica wheels

[astroracer]

A set of poly bushings in the stock arms, a good lowering (as you are planning), good shocks (just go with some good gas shocks, you don't need the adjustability if you aren't' tracking the car regularly), sway bars and lower profile tires will get you where you need to be. If you are driving the car on the street with no plans to make it a dedicated track car you don't need tons of adjustment to make it work.
Example: I did this exact same build style on my street truck 17 years ago. dropped 4 & 6, poly throughout, big sway bar in back and good gas shocks. It drives like it is on rails. The poly bushings do make the ride a bit harsh but the handling is much improved and the truck is fun to drive.

Mark

[jetmech442]

Hey batten,
It sounds like we have similar builds and goals in mind. My ultimate goal for the car was great handling coupling with predictability and stability. Adressing the roll centers front/back were my primary knobs to turn to achieve this.

I have a ’69 442 with an iron block 6.0L(LQ9) and a T56 six speed. I run 285/40R18 up front and 295/45R18 in back (Nitto NT01’s). I have repro-C6 Z06 18’’ rims(couldn’t afford forged rims haha) with 6061-T6 Al wheel adapters.

Up front I have:
• Hotchkis 1’’ drop springs for a small block(580 lbs/in I think)
• 2’’ drop spindles (Classic performance products)
• SC&C Tall upper and lower ball joints (Jointly designed/improved with Howe I think)
o I added the lower ball joint last, and needed to add a 3/4 ‘’ aluminum spring spacer because that extra 1.5’’ drop from the LBJ dropped me too far for my liking (I had it dialed in juuust right).
• Stock lower Control arm rubber bushings.
• SPC upper adjustable control arms.
These are quality pieces and will allow you to set the caster/camber exactly the same for each side(accounting for tolerance/frame flex over the years…etc). HOWEVER, you will need a dedicated race shop to get them aligned. I went to several local shops and they either won’t even accept the job, or they’ll get two hours into it and say they can’ finish. In the end, I purchased the FastraX alignment tool and did it myself. I’m now running -1 degree of Camber and 5.5 degrees of Caster. Adding in the Caster made a world of difference in handling and steering feel. Loved it. Now, you don’t necessarily need adjustable uppers as long as the new tubular pieces have the extra caster built into them. I heard conflicting stories whether the GW’s I was looking at would actually get me that far, I didn’t want to chance it, so I went with SPC.

In back I have:
• 5.5’’ dia ,11’’ tall hypercoil spring (175 lb/s)
• I ended up adding a 1 ‘’ spacer back there too just for aesthetic purposes(wanted the body to kiss the rim).
I also had adjustable upper control arms, which was great for setting pinion angle, but not much else. You want the rear-end to be able to rotate and not bind up, so the rubber bushings are needed to prevent binding. I know it’s tempting to go poly in back to prevent the side to side movement(I did) but the rear end binds sooner and once it binds it snaps back and makes the rear end do 360’s. To prevent the rear end from moving side to side, I purchased the Fays2 Watts link. One of the best purchases I’ve made for this car. Yes the side to side movement is completely eliminated forever, BUT the bigger benefit is that the rear roll center does not migrate anymore with suspension movement. By changing the location of the propeller bolt, I can change the rear roll center and change the car from understeer to oversteer(in less than 5 minutes!). The car feels incredibly stable and planted when I throw it into corners.

For shocks I have the Varishock SS from ChassisWorks front and back. They are absolutely amazing. They are factory valved (no adjustment), nicely compliant on bumps, but the expansion is real heavy which does a great job at control weight transfer. I would have loved to get adjustable shocks sure, but Marc at SC&C turned me onto these at first and told me I wouldn’t be disappointed…I’m definitely not. They’re exactly what I was looking for for a car that will be 70/30 street/race. BTW, if you speak with Marc, he’ll be quick to point out that bilstein has been riding their great name for 20 years on A body shocks-they’re old technology and there are waay better options.

My build thread is here https://ls1tech.com/forums/conversio...onversion.html, I’m happy to answer any questions if you have them. I think you’ve done about 80% or more of the work to get you where you want to go, I think a well matched set of shocks , some extra caster and perhaps a frame mounted rear sway bar would make a big difference IMO. Hope this helps, and again feel free to ask me anything.

[battenheaded67cutlass]

Thanks to both"astroracer" above for the tips and thoughts and to "jetmech442", obviously thoughts from two far different ends of the spectrum, and I can appreciate both ends.


For now, I think we are headed down the path of Option 2, improving a lot of stock components.... Polygraphite bushings and tall lower ball joints, and still up in the air on shocks, but I will definitely check out those varishocks....


JETMECH442, those are the exact wheels we are looking at for the 67..... you have a great looking car


In all honesty, I hope that I get to upgrade the car more in the future, but for now, with the limited budget and somewhat limited mindset of my "old-school" Dad for what mods are worthwhile and which ones aren't, we just want to make the car fun and quick for now.... and get it back on the ground so it keeps the "builder momentum" going

[jetmech442]

For now, I think we are headed down the path of Option 2, improving a lot of stock components.... Polygraphite bushings and tall lower ball joints, and still up in the air on shocks, but I will definitely check out those varishocks....




JETMECH442, those are the exact wheels we are looking at for the 67..... you have a great looking car

In all honesty, I hope that I get to upgrade the car more in the future, but for now, with the limited budget and somewhat limited mindset of my "old-school" Dad for what mods are worthwhile and which ones aren't, we just want to make the car fun and quick for now.... and get it back on the ground so it keeps the "builder momentum" going

Yeah man, I totally get keeping the momentum going and having some great cruises with your dad. I really like the wheels, some of my buds hate em, but I really dig em. Just wish I had bigger brakes to fill them out. (I started looking at your ZL1 setup...). I got my adapters from USWheeladapters. very high quality, and good peeps.

The tall LBJ will drop your front end 1.5'' due to the near 2:1 motion ratio. It will also help correct bump steer. which is nice so that you don't get unwanted steering input when the body rolls in a turn. The tall upper ball joint wont affect ride height, but will make a huge difference in the height of your roll center(and I think adds good camber in a corner). My internet advice(worthless) is to skip the poly bushings and spend the saved money on the tall UBJ's to compliment the LBJ's. I have new rubber bushings all around and feel like the tradeoff between nvh and a tiny bit of response of poly is not worth the price. I know this is generally a heated debate on poly, so I'll reiterate it's my opinion only, but I would much rather have corrected steering geometry first with compliance in the bushings, than subterranean roll centers and wheels cambering the wrong way in a turn.

I've learned a lot from this site and Marc Savitke's book over the past three years, and while I'm no means an expert, I just want to share my opinion to help you go faster within your budget, so I hope this doesn't come off in any way like being pushy or opinionated. Hope to see some video when you get it back on the road!