68 Firebird suspension questions

[Mowjo]

My 68 firebird is clean in appearance and runs well, however its suspension is tired, old and I'm sure somewhat unsafe. As I see it the first order of business is to upgrade from drums to discs out front but how far should I go with other suspension components and in what sequence? What should I do out back? My goal is to not only make it safer but to drastically improve the cars driving characteristics over the original.

Also how big of discs should I install? I'm interested in the Pontiac Rally II rims (16X8?) in chrome or billet to preserve a somewhat stock appearance... what size do I need to clear the discs? How bout tire sizes while we're at it?

[ilovefirstgens]

The search function is your friend!!!

And fyi whatever works for first gen camaros will as well for firebirds, aside from some aftermarket subs which may not be compatable with the poncho motors.


Three things that will help a lot to have sorted out.

1. What are you REALLY gonna do with the car (a cruiser dosent need 14" brakes)
2. What is your skill level, a lot of stuff out there is bolt on, and a lot isnt.
3. What is your budget?!


Good luck, and after a few days of reading old threads you should have everything sorted out. :thumbsup:

[Tom Welch]

Mowjo, I am currently building a 67 Firebird. The following changes were made from stock; 1. pulled the front subframe and rebuilt it with polyeurethane bushings, reset the upper control arm mounts (Guldstrand Mod). installed a ws-6 steering box from a 78 T/A, available at parts stores. Guldstrand shorter than stock front coils. I am using 17" wheels due to availability of 17" performance rubber. 16" is not as readily available in the sizes I chose to use. 17" wheels made it possible to use 13" front rotors from a c4 corvette along with ls1 camaro front calipers. Speedtech makes the brackets needed. For the rear I chose multileaf springs with poly bushings for a 69 firebird, mainly since they were easy for me to get. Alot better than the monoleaf anyway. I am using a 9 inch ford differential from a 65 T-bird that was given to me when the T-bird was scrapped. luckily it was a bolt in job and little fabrication was needed. I am using 17x8" in front and 17x9" in the rear for wheels, shocks will be either Koni or something similar. I plan on subframe connectors in the future. Tires are 255/45r17 in front and 275/40r17 in rear. I did have to fab up some offset spring shackles however to mount the diff. I did this with the shock spacers from 80's Chevy Caprice. They are big steel spacers and they fit perfectly to move my springs inboard 1/2 inch per side. I aint no know it all by any means but so far this has worked good.

[Mowjo]

Thanks for the replies, I will definately utilize the search as I develope a game plan. Fortunately I have a pretty clear idea of where I'm headed (at the moment anyway)... preserving the stock appearance aside from modest wheel & tire upgrades. However I have no reservations about unbolting the antique suspension components and upgrading away.

I can remember loving the 68' I had in high school but hating the crappy suspension & brakes (I'm probably lucky to be alive!) I was wishing then that GM would do just what it looks like they might do now, build a modern interpretation of the camaro or firebird. The only difference was that I wanted the exact same sheetmetal with all the modern engine, electrical and suspension improvements they could stuff into it! Oh well, so all I had to do was wait antoher 20 years and now I can build my ride just how I want it... very cool.

[Marcus SC&C]

There are a ton of good disc brake packages out there for 1st Gens so you really just need to decide how much you want to spend. The carefull with fitment,what fits in a 16" aluminum wheel may not fit in a 16" steel wheel.
As for the suspension first off make sure all of the steerign gear is in good shape,replace as needed with Moog Problem Solver HD parts or NAPA equivalent. Replace the lower control arm bushings with either Moog or Delalum bushings. For the rest of the front suspension there are several ways to go. The factory suspension and steering geometry is (as you know) terrible. You can put bandaids on it but just stiffening everything up until the car is unpleasant to drive or you can fix the geometry and then embellish as you see fit. The angle of the upper arms needs to change. The G mod helps but can cause alignment issues especially if you also lower the car much. That said I recommend it even with many of our suspension packages. The G mod takes the bad geometry and makes it kinda indifferent. You can do much better these days. We have several levels of packages to do that,if you`re interested check out our site. The bumpsteer issue used to be fixed by racers by heating and bending the steering arms (with varying degrees of success). Today you can easily fix it with our tall stud tie rod ends or with one of two new spindles (FatMan or ATS) with relocated steering arm mounting holes. The FatMan spindles are a 2" drop spindle and taller for better geometry but use original bearings and brakes. The ATS units are forged aluminum,and offer better geometry and other advantages but they require the use of 17" wheels. If you`d like the same great geometry with stock spindles we can do that too. Most mods that make any meaningful improvement to the geometry will require some sort of aftermarket upper arms with revised dimensions in order to achieve a decent performance alignment. Adj. upper arms are a nice option because they let you set the alignment however you like with no compromises and no shims. A 1" front bar is often all that`s necessary with revised geometry. In the rear a good set of performance multi leafs will usually do the job just fine. Up front you want springs with a 550-650lb/in rate for good performance and ride. Don`t forget a GOOD set of shocks,don`t cut corners here because they can pay you back bigtime in performance and ride quality. Bilsteins or Konis are an excellent choice or you can step up to a good adj. shocks like the Varishock if you want to get fancy. Last but certainly not least install a good set of subframe connectors! They make a big difference in handling and make the car much tighter all around. Mark SC&C

[Mowjo]

Thanks for the info... I really appreciate it!

OK... heres what I'm thinking at the moment.

Global West stage two suspension kit.

Wheel Vintiques 16 x 8 Pontiac Ralley II chrome wheels. Still not sure what brand or size tires...

Master Power Brakes GM power front brake kit with 12" rotors and 2" drop spindles.

Maybe the MPB poor mans 11" rear drums upgrade (waste of money?)

Considering my modest goals of improved handling, ride & safety... am I on the right track? Are there any problems / conflicts with this proposed setup?
I know Marcus mentioned steering upgrades, are there any other glaring omissions?

[Marcus SC&C]

Global West makes a Stage 2 now too? :_paranoid :P
If you meant a Street Comp Stage 2 your suspension and steering geometry are well covered. It`s going to yield a BIG improvement in both handling and drivability. It lays a really good foundation for any other mods you may make.
Nice choice of wheels. I always liked those. 245-50-16 in front and 255-50-16 out back would be a nice combo for a little more modern look without killing the classic muscle car feel.
Your front brake choice is okay but something with a more modern 2 piston aluminum caliper would be even better. Baer Serious Streets come to mind,smaller dia. but thicker rotors and much more efficient calipers. Skip the drop spindles. They cause clearance issues with the outter tie rod ends and they`ll prevent you from running much back spacing. Worse of all if you get your drop from the spindles you won`t get the geometry gains or additional spring rate you would with a good set of performance drop springs.
Personally I`d skip the bigger rear drums in favor of better front discs or a rear disc setup. Mark SC&C

[Speedster]

Mowjo -
Welcome to the site and nice project you have there. You have set realistic goals and that is good. The only part I would do different is add discs to the back instead of the MPB ones. I think you will find a better balance with disc to disc versus disk to drum. The braking rate with the drums is a lot different. Good 'ol physics.

[Mowjo]

Thanks for the advice... its much appreciated.

I've been pondering the rear drum versus disc issue since I got the car... many friends have advised just keeping the rear drums (probably as a way to keep costs down). However I've kinda felt like its just cutting corners... if I'm going to all the trouble of upgrading why not do it right? Not to mention potential balance issues between disc & drum which I hadn't really thought about extensively.

Marcus, as for the Stage Two kit, here's a link to what I was looking at:

http://www.globalwest.net/Camaro and Firebird Suspension stages for 1967 thru 1981.htm

Again... something to keep in mind is that my goals are pretty modest... I want a car with a great stance, handles way better than original technology allowed, rides firm but comfortable and stops dramatically better. However I don't anticipate putting it on a track and thats where your advice is so helpful. How do I build what I'm after without going over the top... just like your advice on 2" drop spindles, if I don't need em then I don't want em.

[TopEndeR]

Mowjo im in the same boat as you, I plan on upgrading my 1968 camaro suspension to be safe but not break the bank. This site may help you out.
http://www.classicperform.com/camaro.htm

[Marcus SC&C]

Mowjo, oookay they`re using Stage 1,2,3 etc. AND Catagory something something too gee that`s not confusing...
Thing is this. Remember all those suspension geometry issues I covered above? The package you`re currently looking at addresses none of them... The springs are a good idea and they make good ones. We`ve used them in our shop from time to time. Lower arms do..well...nothing at all. Actually that`s not true,they look cool,that`s something. The upper arms add some + caster to the alignment which is good but it makes no fundamental change at all to the ailing geometry. It helps the bumpsteer a tiny bit. Upper arms,theirs,ours,anyones are physically incapable of changing/improving the overall geometry. You have to make vertical changes to make the kind of improvements the front end really needs. You can use taller spindles (like ATS,Heidts etc.), the G mod and or taller ball joints (like we do). Same with the steering,different arms,move the mounting holes (like ATS) or use taller tie rod ends (like us). For example our Street Comp Stage 2 uses taller upper ball joints to achieve much improved camber curves and higher RC location etc. Combine Stg.2 with the G mod and you`ve got some serious performance geometry comparable with modern performance cars! Stg.2-Plus (new and not on the site yet) splits the difference between the two with no mods to the frame (G mod) required. The tall tie rod ends eliminate about 80% of the factory bumpsteer. Overall gains are very similar to the SC-AFX package with ATS tall spindles but of course without the C5 brakes etc. You can see that stuff here http://www.scandc.com/suspensions.htm and diagrams that show the actual geometry improvements here http://www.scandc.com/suspensionspecs.htm You won`t find diagrams like that on most (any?) other suspension company sites because the before and after diagrams would be practically the same! :wow: :yes: If you like GW springs go ahead and get em,they`ll work well for ya. Once the geometry has been addressed by all means get their lower arms with the Del a lum bushings upgrade. They don`t help the geometry but the bushings are really good and the arms are nicely made and look neat. I don`t have a thing against stuff that just looks cool but IMO it`s wise to have a good solid performance geometry first. Mark SC&C

[ProBell]

I would do some research on the drop spindals. I read a Thread on this topic at a PRO-TOURING web site and most of the people recommended staying away from drop spindals. They said it hurt the geometry of the front suspension.

[ProBell]

This is the discussion I saw on drop spindals.http://www.pro-touring.com/forum/showthread.php?t=16609

[Teetoe_Jones]

Just a quick note-

The AFX spindle does not have the above issues until you get over 5+ inches of backspacing. We are also a 7/8" drop vs all the 2" drop like Fatman and Heidts.

Tyler