Z28 steering box

[mabru]

Was talking to a GM mechanic that drives a 1st gen blazer...it's nothing fancy, but he said he put a steering box out a Z28 in it. Apparently it bolts right up in the stock location on out trucks and is 3 turn lock to lock. Says it makes it feel like more of a sports car to drive...anyone ever hear of this, or done it? Gonna see if I can get the part # from him.

[Benoitmusic]

Sounds interesting. Keep us informed

[mabru]

Will do, I think this would be a great mod and relatively easy to do if what he says is correct.

[neo71665]

GM/Saginaw quick-ratio steering box donor car cheat sheet

Late Model 12.7:1 quick-ratio gearbox
ID markings YA, WS and HX
Line Thread Size: M18x1.5 and M16x1.5
Number of Mounting Holes: 3, (missing leg H-pattern)
Input Shaft Diameter: ¾-inch
Output Shaft Diameter: 1 ¼-inch
Number of Turns Lock to Lock: 2 ½ - 3
1984-'88 Monte Carlo/Malibu with Z65 suspension
1983-'88 Malibu, El Camino
1982-'92 Camaro except FE1 soft ride suspension
1984-'87 Regal with FE2 or FE3 sport suspension
1983-'84 Hurst/Olds
1985-'87 Cutlass with 5.0 (VIN code 9)
1982-'85 Trans Am
1986-'92 Firebird except FE1 suspension
1986-'87 Grand Prix with FE2 touring or F41 heavy duty suspension

Pre-'76 12.7:1 quick-ratio gearbox
Line Thread Size: 11/16 x 18 and 5/8 x 18
Number of Mounting Holes: 4, (H-pattern)
Input Shaft Diameter: 13/16-inch
Output Shaft Diameter: 1 ¼-inch
Number of Turns Lock to Lock: 2 ½ - 3
1967-'76 Camaro, Firebird
1970-'76 Monte Carlo/Malibu
1964-'76 Chevelle

1977-'79 12.7:1 quick-ratio gearbox
Line Thread Size: 11/16 x 18 and 5/8 x 18
Number of Mounting Holes: 3, (missing leg H-pattern)
Input Shaft Diameter: ¾-inch
Output Shaft Diameter: 1 ¼-inch
Number of Turns Lock to Lock: 2 ½- 3
1977-'79 Camaro, Firebird
1977-'79 Monte Carlo, Malibu
1977-'79 Chevelle

Jeep/S-10 14.0:1 quick ratio gearbox
Line Thread Size: M18x1.5 and M16x1.5
Number of Mounting Holes: 3, (missing leg H-pattern)
Input Shaft Diameter: ¾-inch
Output Shaft Diameter: 1 ¼-inch
Number of Turns Lock to Lock: 3 - 3 ½
1991-'92 Fleetwood
1992-'95 Grand Cherokee
1984-'93 Comanche
1984-'95 Cherokee/Wagoneer
1983-'86 Bonneville
1982-'93 2WD S-10 Blazer and pickup


Same as a Zq8 box, search next time its been covered.

[90blueS10]

Quote: Originally Posted by mabru

Was talking to a GM mechanic that drives a 1st gen blazer...it's nothing fancy, but he said he put a steering box out a Z28 in it. Apparently it bolts right up in the stock location on out trucks and is 3 turn lock to lock. Says it makes it feel like more of a sports car to drive...anyone ever hear of this, or done it? Gonna see if I can get the part # from him.

are you sure he said z28 and not zq8?

[bg's]

Z28's will work as well. Saginaw is Saginaw. You can install
a Saginaw from a Jeep, a Ford, etc as long as it's a 600, 700
or early 800 series. I run a rebuilt from a 88 Monte Carlo
SS under the alpha code YA. The best were the constant
ratio 12.7/1 box's from the WS6 Firebirds from the late
70's to early/mid 80's.

[rentedmule]

Quote: Originally Posted by bg's

The best were the constant
ratio 12.7/1 box's from the WS6 Firebirds from the late
70's to early/mid 80's.

I was wondering if those would bolt up - The steering on my '80 T/A WS6 seemed insanely quick, even compared to the ZQ8 box in my truck.

[bg's]

^ Yea it's a bolt in. Here is an article on it. Only things one wants to
concerned about are the hose ends for early rides, but most
all boxes are 1.5x14 or 1.5x16mm and go in. Napa sells adapters.

The other thing is on F bodies if I recall correctly, have the stops
set up as to limit turning radius. This was to keep the wide tires
and rims from the factory from hitting the frame. However not
all WERE set up this way. I had a pc that showed the ratios
and turning degrees built into various boxes, but do you think
I can find it now ?..

Anyway here's the pc from the 442 site.

Quote:

Junkyard/factory sources:
For those seeking the ultimate solution, the quickest steering ratios that can be easily adapted will reduce the lock to lock count to a very low 2 1/4 to 2 3/4 turns. These steering boxes are found in the GM successors to the venerable "A" bodies, the 83 up "G" bodies. The vehicles to look for as a donor are:

* 83-88 Monte Carlo SS
* 83-84 Hurst Olds
* 85-87 Olds 442
* 84-87 Grand National/T-Type (Turbo)

These "quickest" steering boxes did not come in every "G" body, so before you take one out of a donor car, or pay the recycle yard for one, always count the number of turns from lock to lock. As stated, the quick ratio's are between 2 1/4 to 2 3/4 turns.

These steering-gearboxes can be identified by a faint and easily erased "YA" marking on the endcap of the steering gear (the end opposite where the steering column hooks up). These cars are not all that common in junkyards, however.

The fastest ratio factory steering-gear had a constant-ratio 12.7:1 box, which should result in just over three turns lock-to-lock in an A-body. In the WS6 Trans AM's of 78 to 81, they used a 12.7:1 ratio, and constant ratio, where the regular T/A and Formula FireBird got variable ratio and 14.1 (or so):1.

You can use the steering box from a 73 or 74 X body (Nova or clones). They are variable ratio and 3 turns lock to lock. Just reuse your old pitman arm. I'm very pleased with mine.

F-body Box:
You can also use a steering box from a late model (90's) Camaro or Firebird (if you count the number of turns!!). The bolt patterns for all these GM steering boxes are identical and will bolt to the "A" body frame. But the internal stops are usually different (due to the variations of the front wheel wells from an F-body to a G-body) The stops from the "G" body cars are closer to those of the older "A" bodies. The F-body steering box might leave you with fast ratio steering but a huge turning radius - you might need all 4 lanes of a 4-lane highway to do a U-turn! F-body cars used a longer pitman arm and steering arm than A-bodies, and the steering box has built in stops that restrict pitman arm travel. The longer F-body pitman arm cannot be used on a G-body because the center link would be moved rearward.

But, according to one source, a late model Camaro IROC box has been installed in a '67 Chevelle with no problems. Even with 50 series tires up front, they don't rub anywhere. Using the Pitman arm from your car on the new box will minimize the chances of interference. If you want to try the recycling yard, the Hollander number for these boxes is 1282.

Be careful comparing the turns lock to lock because the steering boxes themselves have internal stops based on the steering geometry of the car they are going into. While you may have fewer turns, the actual ratio may be the same. You would need to compare turns versus actual front wheel location/angles.

The 82-92 F Body box is a direct replacement for a 70-81 F Body, and that is a replacement for the 73-88 A/G body. And even some Fords! The newest box is better, better road feel, better seals, etc. GM pretty much used the same mounting in all, some only used 4 of the mounts, some had 5. Obviously 4 is fine.

You can usually find these model 800 boxes in the junkyard for a very reasonable price. A box off a late model Camaro (82-92) will also work. They are 12.7:1 ratios and take approx. 2 3/4 turns lock to lock. I put a 84 Monte SS box in my 79 Cutlass. I paid $10 for the box and $25 for a rebuild kit.

While the Model 800 box will bolt up to the A-body, I believe that there are two problems (neither fatal). First, a new coupling is required to connect to the A-body steering shaft. Second, the Model 800 has different internal stops which limit the turning radius when used in the A-body chassis.

Potentially a better solution is a setup sold by Power Steering Systems in Springfield, MO., phone (417) 864-6676. For $189.95 plus about $20 shipping they will rebuild your original A-body power steering box using a brand new 12:1 worm gear and piston set. This provides the quick ratio (greater than 3 turns lock-to-lock) with a true bolt-in system and no downside. And, of course, the box is rebuilt with all new seals and bearings.

The owner, Chip, has a 69 442 and claims he recently converted the steering boxes for three different 69 H/Os.

I was able to convert my 1970 power steering pump to 1980 power steering pump hoses by replacing the fitting that screws into the pump body with the one from my 1980 power steering pump. They are very different pumps, if you have an old Olds 1970 and older compare it to a later 70's and up pump, they are compatible with this change. So, you will need the hoses from the year of the power steering box, and then you may need the fitting on the pump that matches those hoses, if there is a difference.

One style is flared, and the newer one is flared with an o-ring at the end. Done to reduce leaks.

Use the 82-92 Trans AM WS6 Box. Newest is best, has best road feel, and fast ratio was only avail on WS6 cars, not plain jane Trans AM/Z28's. Get 1992 Trans AM WS6, fits all 70-81 F-Car, does not have the short stops, and you get the best there ever was in the power steering boxes that GM did for high performance. And the WS6 box is supposed to be constant ratio, not variable ratio. So double goodies from the WS6 box, 1982-1992. The 78-81 WS6 Box was constant ratio, and did have the 12.7:1 ratio (2.25 turns lock to lock, that is full left to full right boys and girls....) (Most are 3 turns lock to lock, 15.7:1 or so ratio) and the ratio from middle to sides remains constant, almost ALL cars do NOT have constant ratio, they have a variable ratio that does not turn much at the middle, but when you get past 1/2 turn left or right, it gets progressively faster for easier maneuvering like parallel parking, etc. Only WS6 Trans AM, Corvette and special cars got the constant ratio.

Nearly ALL GM Chassis can use the 1982-1992 PS Box, so if you are going to waste any money on one, get the best, don't waste money on the older 2 gen F car box.

F-body cars (Camaro's and Firebirds) have a faster steering-ratio than our stock A-bodies, but not all of them have the 12.7:1 ratio, and these steering-gearboxes can cause problems when swapped into A-bodies; all of them were designed to use a longer steering-arm, so when swapped into an A-body with the shorter steering-arm the tires will no longer turn as far to either side, which will increase your minimum turning radius, making U-turns a thing of the past. The longer F-body steering-arm and idler-arm cannot be used on A-bodies as the steering centre-link will hit the frame crossmember. In addition some of these cars used a different type of fitting for the power-steering hoses (using an o-ring), so you either have to change your hoses and power-steering pump, or change the hose fittings in the steering-gear. Lee Manufacturing makes adaptors that convert the newer fittings to accept the older hose-ends. Camaro's and Firebirds with factory handling packages are most likely to have the 12.7:1 ratio gear, these include Z-28 Camaros and Trans Am's and WS6 Firebirds. One listee said that the 1992 WS6 Trans Am steering gear was the best of the factory ones. This one has both the new hose-fittings and the limited turning-radius, so be warned. It is available from AutoZone for about $200 for a rebuilt one, be sure to specify WS6 or high-performance suspension option to get the fast-ratio box.

The internals from these fast-ratio gearboxes can be swapped into the steering gear from your car, converting it to fast-ratio steering. This looks like a fairly complex job. For some information on gearbox swaps go to Jim's Muscle Car Page http://members.home.net/jimmy4 and follow the link for Steering Gear Swap Info. The end cap on the steering gear controls the the internal stops that limit total travel of the steering arm, so by using your stock steering gear endcap and housing along with the fast-ratio internals your turning radius will be the same as before.

While these late model steering boxes will bolt into the chassis, two modifications in the area of connecting them up are needed. You need a hybrid coupler (the "rag" or fabric connecting joint) from a '79 to '84 Chevy pickup truck to adapt the older design steering column to the new design steering box, and you need to change the way the power steering fluid connections are made. Adapters to convert the metric fluid connection lines to earlier standard fittings are available. The newer boxes use an o-ringed metric end while the older boxes use the common 3/8" flare end. NAPA sells the required adapters. They are:

* Weatherhead #1445: 3/8" is 5/8 18 - 14x1.5
* Weatherhead #1446: 3/8" is 5/8 18 - 16x1.5
* Weatherhead #1447: 3/8" is 5/8 18 - 18x1.5

Since the boxes varied slightly from model to model versus the fluid line connections, you should order all three. Take your "new" steering box (or the newer lines for comparison) with you when you go to the parts store. They might even let you pick the 2 you need and not buy the unneeded adapter.

The GM part number for _brand new_ boxes of the latest, fastest ratio is 7839897. According to Drew Koba, Olds parts guru and OCF Chapter Representative, these boxes are still available. They list for $677 (ouch). But Drew has recently convinced his employer (Fountain Olds) to sell GM parts to club members at a substantial discount.

As noted above, to use the late box with early steering columns, the Chevy pickup truck coupler is needed and its GM part number is 7826542 ($68.25 list, again a discount is available). I would strongly suggest using a new coupler rather than a used one when changing your steering box.

Drews numbers at Fountain are: (407)888-1455 and 800-456-8701. Remember, all OCF members get discounts on parts purchased through Drew. And, if it exists, Drew can get it!

Results:
For the record, I performed the change to a '70 steering box and wheel on my '67 Cutlass 442. The improvement is phenomenal. You may see me checking the GM section at the local "Pick 'n' Pull" yard myself looking for that super quick box.

Ken Crocie's used a 84 Trans Am steering box that has 2.5 turns lock to lock on his 64 GTO. There is supposedly a problem with internal stops in the F body box so that you won't be able to turn the wheels all the way and have a wide turning circle. It looks like you can simply take the box apart and reuse part of your original box to get rid of the stops. The stops are in the end plate which faces forward and down when the box is in the car (the round piece). The reason for all this is that the F bodies have a longer (so I've heard) pittman arm which you can't use in an A body since the center link would be moved rearward.

HTH's.

[bg's]

Oh here it is. This will help define turning radius and lock to
lock pins of the wheel..

http://www.chevelles.com/techref/shea_3.html

[Daveman2]

I got one for my 2nd gen out of a '91 Trans Am GTA. It did reduce the stops a little ( I have a 4X4 box which turns farther), but it didn't make much of a difference in my turning radius.

Compared to the shitty variable rate steering, which had me jerking the wheel left and right 45* constantly on windy roads just to not go off the edge.
After the 12:1 box I LOVED my steering, and not having to turn the wheel as far. 3 point turns are alot nicer, I don't know how anyone could drive a stiff lowered truck on a 16:1 variable box after experiencing a 12 or 14 ratio box.

[bg's]

Quote:

I don't know how anyone could drive a stiff lowered truck on a 16:1 variable box after experiencing a 12 or 14 ratio box.

^ So true

[mabru]

Good info bg's..exactly what I'm after

[drb930]

Subscribed!

[sdimedan01]

I just swapped a quick ratio out of a 86 trans am into my second gen. it bolted up just fine as the donor sheet says above. They only thing you need to remember is to use the S10 pitman arm. The pitman of the firebird was about a 1/4-1/2" long and it caused the drag link to hi thte frame, limiting the steering. Definitely recommend it to anybody woudl wants there truck to handle. This is a noticable difference in the amount if steering input needed.

[bringtheboom]

anybody know what the ratio of an 89 t/a GTA box is? it wasn't in the list above.

[bringtheboom]

ooops, never mind, just found it. 12.7:1. a buddy of mine swears there is a 10:1 saginaw box, cant remember what he thought it came in. anyone ever heard of one of those??

[bg's]

^ No. If anyone would know it would be Jim Shea but
he's not avail. If any others would know, it would be
the guys over at Mullins Steering Gears in Az.

They are one of the very best when it comes to steering
issues.

[tdrrally]

http://www.speedwaymotors.com/Sweet-...xes,23591.html
here is a link to an 8:1 and 12:1 steering boxes

[ZQ8 Blazer]

The ones in the firebireds and trans ams are different right? Same with the Camaro's?

[sdimedan01]

You want to make sure you are getting a box from a car with the heavy duty/sport suspension. The trans-ams, Z28, and SS can with these too.

[ZQ8 Blazer]

ok thanks

[fastr68]

almost any 60s throguh 90s car box will bolt on fine depending on shaft splines and pitman arm shaft diameter though

i have an 83 trans am box on my 91 2wd

exact same splines both ends perfect

same lines too

lines are another change though to watch out for

90s ones are metric o ring style line ends

older ones are flared SAE

so,.,..,

this change was in 1980 on full size trucks

and on cars and s-series it was pretty random from what ive come across over the years

same with wheel studs going from 7/16" to 12mm

random as hell.

s-10 and f body etc changed early

other cars like the caprices and such didnt until later on

cars and s-series boxes mount to inside of frame rail

full size trucks before 88 mounted on wrong side, outside

so if you remember that then you got the basic concept of it all

s-series = g body chassis frame box style unlike the full size trucks which are C channel open rails

but even in '88 when that changed the boxes still wont work on cars and s-series

too big physically.

i have a '94 full size truck box sitting here right now if you want pics and numbers, and i have a few s-series/car boxes here also currently