'68 Camaro stock subframe mods.........
 

Hello all,

I just found this site about a week ago and have been looking for some info on modding the stock subframe on my '68 Camaro. Money is a big issue so I need to be frugal. It's not so much about appearance for me, it must work! I will be using the car for primarily autoX and big track venues, I want to be competitive! I gathered bits and pieces from different threads, and this is the conclusion I have arrived at - let me know if I am close?

Tall spindles or tall ball joints need to be used to correct geometry, are tall ball joints reliable?

Bumpsteer is an issue, can this be fixed with a power R&P?

I see coilover conversion kits, what will these do that a good shock and stock style spring can't do other then easily adjust ride height?

It looks like one of the bigger advantages of an aftermarket sub is the ability to run a wider wheel/more rubber. It's also probably stiffer and has better geometry.

Can I mod my stock sub geometry to be competitive with the aftermarket subs?

I've got tools and time, but not much money.

Hi Pete:

Welcome to the site. There is a wealth of knowledge and knowledgeable folks here. I'm sure they can and will be able to help you out.

I'll try to offer what I can to help you out on your questions below. I'm sure there are others on there who can help you even better, but, since I'm first to reply, here it goes:

Suspension geometry isn't great on these cars as you know. One low cost fix is the "guildstrand mod". You can read more about it here:

https://lateral-g.net/forums/showthread.php4?t=20492

Bump steer, to my knowledge won't be fixed with a rack and pinion. I don't believe it has anything to do with it. Bump steer is the changing of your wheels direction as it travels through the suspension travel. Ideally, you want 0 bump steer, so your wheels stay pointed in the same direction no matter where they are in the suspension travel. Bump steer can change the direction of your car on you as you hit a bump, go around a curve, etc and can cause you to reduce/ lose control of your car. not good.

To fix it, you want to improve the suspension geometry. doing this optimizes the camber curve and eliminates bump steer. this is where I believe the correct length and located control arms come into play. the taller spindles help change the geometry of the stock suspension by altering the location of the pivoting points in your suspension.

The coil overs allow for quick ride height adjustment and may possibly reduce unsprung weight. Also, since they are a self contained unit you may not need a spring compressor for spring removal/ installation. then again, if you're careful (and I'm not advocating it) it is possible to remove and install the springs on the first gen f-body without a spring compressor.

I'd do more searches on the aftermarket subframes. It seems from my readings that many aftermarket frames are weaker than stock. You can weld up the factory subframe for increased stiffness. you can also do other things like use solid body mounts, subframe connectors, roll cage, etc. all these things in combination will substantially increase chassis stiffness. These are the types of things i plan do do to my car.

I think with the above mentioned stuff plus some research on this board you'll find all the tips/ tricks to do what you want. many of the aftermarket parts are for show and convenience as well. Like you said, you want function, not looks.

People raced these cars long before all these trick components came out and were successful. Hand built fabrication and ingenuity worked for them. I'm sure you can do it, too.

Of course, this is my opinion. Everyone has one. I hope this is helpful.

-Brendon

Thanks for the reply Brendon :cheers:

That link is a GREAT find - Thanks for sharing!

You are the second person that has told me that "some" of the aftermarket subframes aren't that strong, must be some truth to it. While for me, finances determine I stick with the stock sub it's good to know it can be brought up to todays standards. The one limitation that still remains is tire size, correct? The aftermarket still holds an advantage.

I have already done some of the things you suggested: solid mounts, subframe connectors and a 6-point roll cage - these have really stiffened the car up! Some forward struts would really help alot. If you think about it the whole front subframe is held to the body with just 4 main bolts!

weak aftermarket frames are still stronger than the stock ones.

I'd recommend getting your frame blasted and then weld all the seams. You will see why after you get it back from the blasters. We made a bunch of money fixin the stock frames.

They can be made to work very well.

Def recommend the guldstrand mod, and maybe a relocated lower arm to increase room for more caster ability. Get a good box, a 2nd gen fast ratio is a cheap and easy add on.

If you can weld make your own coil over mounts and subframe connecters.


Vince

Thanks for the advice Vince!

Welding the stock sub makes good sense - GM was a little stingy on the welds!

Tell me a little more about relocating the lower arms, haven't heard about doing this before? I planned on getting tubular upper/lower arms and tall spindles (haven't decided whose yet) - will these accomplish the same thing?

I already have a 6-point cage and solid subframe mounts. I installed some bolt-in Moroso subframe connectors many moons ago which I need to replace with some weld-ins.

I was thinking about welding up some forward struts as they seem to add quite a bit of stiffness right where it needs it most.

At first I wasn't considering coilovers for the front but the more I think about how the car will be used it's beginning to make more sense. Making mounts to accept a "standard" coilover also makes more sense $$wise then using one of those conversion kits, especially when it limits me to using a custom shock.

I like the idea of the 2nd gen box because it's inexpensive - it's just so darn big and heavy! Not sure if it will fit with the big-block?

The 2 gen steering box is no bigger in size than the 1st gen box. And if you really want the car drive it's best dont put a big block in it unless the block &heads are alum. or you're willing to move the motor back about 5-6 inches.You will have to much wt.# hanging over the axle centerline.Most of the after market subframes are built & engineered really well.And most of them work very well also.I have bought others sub frames & built my own from scratch. And been very happy w/ both.Scott

Hi Scott, thanks for setting me straight on the 2nd gen box. So the power box will slot right in?

The BB has been in there for quite some time and will likely stay there until I win the lottery! I know it's heavy but it's what I have to work with for now. It does have aluminum heads and I've got an aluminum rad, glass hood and inners and the bat is in the trunk, about as good as it's gonna get for now.

It's not that I don't 'want' one of the aftermarket subs, it's just not in the budget.

You can hang with the LSX guys all day long with that big block. Concentrate on getting a well balanced chassis and the driver. :thumbsup:

Thanks for the input Todd, wasn't sure if I was :beathorse or not!

I agree with you about the 'balance' - just not sure how to get there other than trial and error. That's why I'm asking for some advice from the people who have 'been there, done that'.

Maybe I should have asked this question: How do I get my BB '68 to run with the LS boys on a budget :lol:

Thanks for the insight :bow:

Hi Pete,

The coil over part should be easy as you are starting from scratch. Find your desired stroke and build around it.

On the lower control arm you can either repocket or buy a tubular arm. We used to repocket before the arms were available. Most add caster and are available for coil over mounting. I'd say put your money there.

Also try to find a cheap LSX engine. They are popping up everywhere. Take a visit to your local engine machine shop. You'd be surprised on what you'd find poking around. Big blocks are great but if you can find weight loss without loss of power go for it. I found an LQ9 core for $400 and it would make a nice track motor.

Vince

Thanks for the input Vince :thumbsup:

Sounds like a good plan, so who's arms would make your "top 3" list?

Was looking at Afco coilovers, good/bad?

While I think I will ultimately end up with an LS motor the BB will have to do for now. How much less does the LS motor weight? I was thinking the L92 or LS3 would be the way to go with the alloy block but I'm sure an iron block motor would work just as well with a little more wieght, I wonder how much more........

You don't need to lose the big block. The low end torque is ideal for autocross and road racing. With aluminum heads, radiator, battery in the trunk, you are in small block territory anyway. I've raced my car with a steel block and now ZL-1 aluminum block. It doesn't make that much difference. Honing in your chassis and your skills will make a much greater difference. LSX this, LSX that. :rolleyes:

Thanks Todd

While the BB is staying for now it's not very streetable. I built it with intensions of drag racing so it's got 12.5:1 compression a really lumpy cam, Holley Strip Dominator intake and 850cfm dp. It ain't a pump gas motor! It's also got a deep oil pan with little baffling. The heads are early GM aluminum closed chamber with LOTS of work done on the exhaust ports BUT it wasn't built for unleaded fuel. And it's a baby at only 402ci.

While I haven't crunched the numbers as to what it would cost to make this thing live on pump gas I have a feeling it may be close to a used LS motor. While I know It would cost more to install, the EFI would be very welcome. Our fearless leader Scott told me he knocked down 22mpg with his modded LS7 - I don't think that is possible with a BB? Bottom line is I want to USE the thing!

I get about 24mpg on the highway, but I could probably get better. :cheers:

24mpg :wow: that's what I get with my daily driver! Nice :thumbsup:

What are you running for rear-end gears, didn't see it mentioned in the Camaro Performers article?

That's a different story. There is no doubt the LSX is the most economical option. I thought you had a decent street power plant.

I'm running 3.70's. I'm pretty happy with that setup with a 26" tire. :cheers:

I would be very carefull full welding the seams on the subframe. Heat will warp the you know what out of it, and it will provide very little benefit except looking cool all smoothed. If you do weld it up solid, do it in stiches 1 to 2 inch at a time and bounce from side to side to allow cooling beween welds.

As for mods, IF your using aftermarket control arms a simple re drill of the upper control arm mounting holes on the subframe below the factory holes will improve you camber gain. And a set of geometry corrected control arms will increase caster.

A good set of coil springs like Hotchkis, some good shocks (Hotchkis are great NON adjustable on a budget, A hollow sway bar (Hotchkis again) and a 600 steering gear, some tie rod stiffeners, and you have a really nice frame for $2500!

All great advice. Also, instead of relocating the upper control arm mounting holes (the Guldstrand mod), you can use either tall spindles (not drop tall spindles) or tall ball joints.

Understood, I've made some wavy stuff before :_paranoid Do you think it would be worth the trouble of pulling a finished car apart to do this mod - well, I suppose I could do 75% of it without pulling the subframe? I was also thinking about some forward struts to help stiffen the front - worth the trouble?

My only question here is who's arms are "geometry corrected"? The actual changes made by the various aftermarket arm builders seems to be a secret! They list the material they are made of, which bushings and balljoints they use but they don't specifically list what the change in geometry will be (did I miss it somewhere?). Reading many other posts in this forum it seems you would be the man to ask :D

That all sounds good. So you recommend the 600 box over a rack?

This is one area that I haven't determined what to do with yet. I was looking at changing my drum - YES I have drum brakes in the front - to Vette Gen 5/6 stuff using a Kore kit but I need to do some more research to see if it will work with my spindles or if I need to change them out anyway. Upgrading to the ATS tall is a good chunk of change and I don't know if I can go about it any other way:question: There doesn't seem to be to :question: many fans of the extended balljoints

Take a look at SC&C's website (http://www.scandc.com/index.htm) and talk to Marcus. If I didn't have the ATS spindles for my '67, I would be all over the SC&C setup.

Hey Mike, I checked out the site and after looking at Kore3 brake setups it's getting pretty close in price. If I go with the Street-Comp Stage 2-Plus which uses my stock spindle and longer upper and lower BJ I need a more expensive brake kit because they need to use a new hub. If I go with the Street-Comp AFX I can use the less expensive brake kit because it already has the vette hub. So in the end the price difference between the two isn't that much, $320 and I don't have to trust my 30 year old spindle with it's small bearings. That was easy!

Now back to arms, I do like the adjustability of the SC arms, could be a help at the track to dial in the car - are they as strong as the non-adjustable arms, I don't know but I believe they are basically Nascar type arms. They are also quit a bit less money then the Hotchkis stuff. Am I paying for a name or a better product? Again, I don't know, that's why I'm asking the pros :hail:

Sweet, Thanks Scott :thumbsup:

holy cow Pete, your plans changed quite a bit from your first post. LOL


Maybe we should talk about your total budget first then go from there.


Also I hope you didn't think I was putting your BB down, im a BB guy from birth and had several BB SS cars early on, 68 427 Chevelle, 69 396 Nova 65 396 Chevelle 454 Monte Carlo and even have a 496 in my daily driver. Then it went to big cube small blocks 383, 391 ,406's. But man you just can't beat the HP and MPG numbers these aluminum cans put out, for less money.

Vince

For what it's worth, I'm using the SC&C (SPC) arms on my '67. I like the idea of eliminating the shim stack for things like the Hotchkis Chassis Max Handle Bars.

i have removed my Global west arms (that look great, and are twice as heavy.. AND are alittle too long, so i needed 3/4 inches of shims to get the geometry right)

and i have installed the SC&C lightweight arms.... and can onmy recoment them... i got the screw in nascar type balljoints..

they are half price and atleast as good as the GW.. and the loads on the UCA arent that great anyway.. you can only put as much moad on them as the upper balljoint stud can transfer without shearing off.... (look at a C4 UCA and see how flimpsy they can be and still be safe for racing)

I have no idea what you are talking about :unibrow:

Well, I guess there are a couple of ways to look at this. I've owned the car since 1979 and have put about 300 miles on it. The last time it was driven was in 2000. My time frame may be a little different then most!

I'm not the kind of person that will spend large sums of money on a whim, I will educate myself and research it to death before I start spending money. That's where I am right now, research mode. I have a blank canvas in front of me and a goal:the car must be 1:competitive and 2:functional. Pretty doesn't figure into my goal with the possible exception of wheel choice but only after meeting goal 1 and 2. Do I need a new subframe to be competitive, I don't believe so. Will I need to upgrade my front suspension, yes but with what? Will I need to upgrade my 4-wheel drum brakes, yes but with what? What will meet my requirements 1 and 2 without "overkill" or "overspend" to get the job done? It's not so much about; I have $xxxxx to spend - what should I get? as it is; what do I need to do to get my car to meet requirements 1 and 2 and be "capable" of finishing in the top 5 to 10% of an Optima challenge suspension wise?

No worries :cheers: and I agree, today's technology has drastically improved the breed!

Good point and something I hadn't thought about. The adjustable arms really do appear to have a lot of advantages, with a good price to boot!

Good information, Thanks for sharing. One thing that's not mentioned is the actual material used for the cross shaft - steel or alu and the bushing, are they delrin or? Tell me a little more about the screw-in balljoints advantages.

Function over form, lighter weight and half the price - what's not to like:woot: :cheers:

The suspension is only a part of being competitive, with many people arguing the biggest aspect being the driver. Narrowing all factors down to front suspension, you can definitely be capable in a stock subframe car.

If you're going to go stock subframe there are a few ways to approach it.

Cheap - Tall ball joints or guldstrand mod, new shocks and springs, some form of a-arm upgrade (upper adjustable and stock lower), sway bar and steering upgrades.

Medium - Tall spindles, new adjustable shocks and springs, sway bar, new a-arms.

More - The above plus double adjustable shocks or coil-over conversion or more extreme changes.

I don't have the perception that there is a huge gap between one option and the next. The biggest gap is from stock to any upgrade, and then things get incrementally better or more adjustable.

I'm going with the medium cost option and expect it to be competitive having spent a lot of time reading about components and piecing them together to make a good whole. That's one of the bigger tangible benefits with the aftermarket subframes, in that you can just order it and all of the pieces work together without you having to do much thinking.

Brake wise I have AFX spindles so I just went C5 brakes which are cheap, have lots of pad options and aren't uncommon on track cars. I intend to leave the option on the table to upgrade to C6 ZO6 brakes in case I need to,

Great post :thumbsup: This is the kind of info I am looking for.

I agree that going with the full sub upgrade is a no-brainer approach to a decent setup - at a cost. You have obviously been researching this longer then I have, care to share the setup you have decided to go with?

One thing I have discovered with the brake setup is that it will cost about $400 more on the stock spindle then the ATS spindle because you need a new hub and brackets. This narrows the price gap between the stock spindle and AFX spindle enough (in my book) to upgrade.

I've done "Cheap" on my blue '68 - the car I've been driving for about 6 years now - Guldstrand mod, stock UCA/LCA with delrin bushings, AFCO spring adjusters and AFCO springs, Koni adjustable shocks, Hotchkis front sway bar, 3rd generation IROC steering box. The only thing UCA's will do for you is maybe reduce tire rub if you run a lot of caster. Also, you don't need new hubs for C5 brakes, you can have your current hubs turned down to fit inside the C5 rotors. You will need brackets, but they're pretty readily available for not that much. It's a fun car that is more capable than my driving can possibly show off.

I'm doing "More" and then some for my project '68 - 21st Century Street Machine subframe, Lateral Dynamics 3 link rear, and so on. If you do the work yourself, and part select yourself, don't let anyone tell you it's a no brainer. I've spent 2 or more hours planning for every hour actually working on the car.

Finally, I'm planning/assembling parts for "Medium" for my project '67 - SC&C (SPC) UCA/LCA, ATS tall spindles, AFCO spring adjusters and AFCO springs, Hotchkis sway bar, Bilstein shocks, 3rd generation IROC steering box, etc.

Of the three, "Medium" so far seems easier than either "Cheap" or "More" because it's pretty much a bolt on and go as compared to the other two; but then again, I'm much more knowledgeable now than I was when I started on "Cheap."

here is my setup... OEM subframe + reweld, ATS coilover brackets.. I found here "used" which means just taken out of box ... for a steal... ATS tall spindles, SC&C arms.


Point is don't box your self in... if your not in a rush you can get what you want if you watch the classifieds..

I think you need to come up with a goal for your overall car as it's easy to focus on one aspect like the front suspension and not consider everything else. Every choice affects other choices and they all should fit together, like it's pointless to have the best suspension if the car weighs two tons, or you have a 200 horsepower motor.

My subframe plan right now includes the following parts most of which I have:

AFX tall spindles - Had these for a long time now
SC&C adjustable upper arms (not the lite ones sadly)
Hotchkis sway bar - Probably my least researched item
Detroit speed lower arms
Varishock single adjustable shocks
Detroit speed 2" drop coil springs - Any brand would probably work fine
DSE or Speedtech steering box - Have not gotten this yet.
C5 brakes - Cheap and effective.

In an effort to lighten it and to make it stronger, it has some other modifications, mostly replacing the front crossmember and re-welding.

Hey, good info - Thanks! It confirms what I was thinking. Medium+ is where I think I am heading. ATS spindles because I really don't like the idea of stressing those 30+ year old small bearings with FAR more load then the engineers ever intended. Uca and Lca to shed some wieght and correct geometry a full coilover because they cost less then a bolt-in coilover kit and not a whole bunch more then a spring and shock setup. Actually for me researching what needs to be done is just as enjoyable as building :lol:

You know I never really gave much thought to looking in the classifieds, could really save some $$$ I'm not in any rush to get it done so time is on my side. I hope I'm lucky enough to find the big ticket item - Wheels - used!

Thanks :cheers:

Yes I agree, and I do :thumbsup: While I haven't fully decided what I am doing in the rear it will get a similar treatment to compliment the front, either an Alston Gbar or maybe some form of 3 link. Don't worry, I will start a new thread on that once I get the front sorted :lol: The BB will likely be replaced with an LS motor, likely a 6.0 or 6.2 - mostly stock at first and will build it after it's in the car with a target of around 600hp at the crank.




Looks pretty similar to where I am headed,
AFX
SC&C UCA
not sure about sway but I would like adjustable, hollow to save some lbs
LCA, not sure as I need a coilover lower
full coilover, I will make my own top mount
steering box?
brakes, If C5's will get the job done - Great as they are about half the price of the Z06.
add some front struts

Looks like I'm getting it nailed down, Thanks for your help gents :cheers:

just to answer.. the crossshaft is steel, the lightweight arm uses steel on hardened steel as bearing instead of bushing.. the non lightweight arms uses a high durometer rubber.. needless to say i got the steel on steel type... less friction, and no rubber to rot (just grease it once in a while)

Thanks Deuce :cheers: