Equipping a G-Body with a manual trans

I'll probably update this more as I attempt to consolidate the info from various posts I've made. I'll start with mechanical linkage for a traditional Saginaw/T-10/Muncie. Some of this info I got from t5montecarlo's site (http://www.garage-scene.com/t5-into-ag-body/) so I give kudos to him of course 😀
Until recently nobody made a reproduction G-Body clutch fork. StreetBu on MalibuRacing.com (he may be here too) first made the post about it. It appears there were two different designs, one in '78, and I believe it changed for '79-'80. You can get it from The Parts Place. They also make a reproduction shifter hump, where coupled with the reproduction plastic cover, trim ring, and shifter boot, you can finally add the original 3- or 4-speed look to a G-Body.



Clutch fork (Part #MT10680Z)



Manual trans hump (Part #MT6672Z)


They also have a somewhat complete kit to convert over to a factory-style setup, but doesn't include the hump/trim/boot. It costs $289, I've seen other kits upwards of $475 :shock:
PN MT9895Z
Kit includes:
*Brake & clutch pedals
*Z-bar
*Z-Bar bracket
*Pedal pushrod
*Clutch fork boot
*Clutch fork
*Clutch fork pushrod
*Clutch fork ball
*Clutch return spring(s)
*Hardware kit (Engine ball stud, frame side ball stud, 1 spring clip, 1 felt washer, 2 nylon bushings, 1 lock washer, 1 nut)

A couple pieces this kit is missing are the clutch safety switch (not required but helpful in keeping the car from starting in gear and keeping it in factory-correct working order), and I believe there is a rubber stop for the pedal to prevent excessive pedal travel. There is also a clutch rod firewall boot that is missing.

For the trim plastic, trim ring, shifter boot, clutch pedal boot, and clutch safety switch, they (sans clutch switch) can likely be sourced from a couple different places, but for ease of this post I used Dixie Monte Carlo's site.
Trim plastic, pn DM90802


Trim ring, pn DM90809


Shifter boot, pn DM90801


Clutch pedal boot, pn 90811


Clutch safety switch... couldn't find much more info on replacing one besides the GM part number, which appears to be of either 344889, 303651, or 469085. It appears one from an older model may work (found at The El Camino Store), but it doesn't have the shaft/clip like the one from a G-Body has, so you may be able to use a shoulder bolt with a nyloc nut.
Original part



Part #06-0077


For those who already have the factory linkage, but their setup is getting slop in it, or just want an upgrade, Speed Direct has a tubular linkage setup (clutch rod, pedal to z-bar rod) with spherical ends on it that take out the slop that the original setup has.

Bellhousing/fork/flywheel info

Most of the G-Body bellhousings won't take a 168-tooth manual trans flywheel, so you need to use a 153-tooth. Be sure to know the year of your engine when/if you need to buy one, one-piece rms blocks started in '86, 2-piece engines are pre-'86.
Pre-'86 blocks use this flywheel


'86 and later engines use this flywheel


The curve of the fork is required because of the floorboard, and the geometry of the linkage. If you drew a line to the crank centerline from where the clutch pushrod meets the fork, you'll see it's not simply horizontal like you would see with all the straight forks, and this is why the G-Body bellhousing won't work with a standard clutch fork. You could use a straight clutch fork with a couple different bellhousings though.
'82 F-Body (casting #14037657, fork #140376472)


'84-'88 Corvette (casting #14048867, fork #140662352)


Lakewood 15015 bellhousing (PN 15015, fork PN 15500) - this will also fit a T-5 trans, as you can see the canted bolt pattern.


I believe most of the linkage compatibility comes into play with where the ballstud is on the block.


If the #7 tube doesn't come down almost vertically, it will be in the way of the z-bar.

Saginaw/T-10/Muncie info

All 3 transmissions will bolt up to the same bellhousing, and (I'm 90% sure) have the same transmission mount location. I don't know the specifics on all the output shaft specs, but they will have either a 27-spline shaft (same as TH350), or 32-spline (same as TH400).

Trans case/input shaft i.d. (number of rings around the shaft) & ratio info:

Hurst shifter application info for G-Bodies:

The '74-'81 F-Body with a T10 (w/o console) uses the exact same shifter body and stick, but uses installation kit 373 8609 (if you're swapping a BW T10 in).

The '70-'72 (no '73 listed...???) F-Body with a Muncie (w/o console) uses shifter 391 6848, same body but uses stick 538 6836 (538 8009 can likely be used since it's the same body), and installation kit 373 7897.

I figured an F-Body would be the closest to a G-Body since the overall body is a similar size.

T-56 info

This post may be a bit dated currently, I wrote it a little over 2 years ago.
Basic T-56 info
TREMEC'S OFFICIAL PAGE FOR THE T-56

A basic rundown of what's available as far as GM T-56 transmissions (thanks Chree):

• GM LT1 T56 ('93-'97 F-Body): Works with Gen 1 SBC, you use the LT1 bellhousing and F-Body hydraulics with John Bzdel's pedal.
• Aftermarket T56: has an adapter plate to mount the T56 to a traditional SBC bellhousing.
• GM LS1 T56 ('98+ F-Body, GTO, etc.): can be mated to SBC with the McLeod modular bellhousing. LINK

Linkage
There are a few ways to install a T-56 into a G-Body, depending on what transmission you use and/or what linkage you use.
Starting with the linkage:

• First, there's the factory F-Body linkage, which utilizes hydraulic master and slave cylinders. You can most likely pick these up at a local salvage yard, or purchase them new from an auto parts store (much cheaper at a salvage yard, also more chance of premature failure). There are also two types of available slave cylinders.
  One mounts on the F-Body bellhousing:
  
  
  
  And the other actually slips over the input shaft, the cylinder itself pushes on the thowout bearing:
  
  
  
  Weir Hot Rod Products also sells a new bellhousing to use with the F-Body (OEM) T-56, it includes a self-adjusting hydraulic throwout bearing, steel block plate (clutch cover), pressure and bleeding tubes (mounted on slave/t.o. bearing), and new bellhousing and transmission bolts. They also recommend a master cylinder from either McLeod or Wilwood for proper operation. This would be a good upgrade if you came across a screamin' deal on an OEM T-56 without a bellhousing, the kit also allows you to use a standard starter, where (I believe) the starter required the factory bellhousing is F-Body-specific.
  
• Next is the factory style G-Body linkage, which you can now find numerous places, including eBay and various aftermarket suppliers (Mike's Montes, El Camino Parts, Honest Charley to name a few). Also keep in mind if you are switching from an automatic to a manual that you will need to relocate/remove the vacuum/wiring that runs through the firewall for cruise control, as it uses the same hole. Here is an exploded view of the entire pedal/linkage assembly:
  
  
  
  EXCELLENT LINKhttp://imageevent.com/publicgallery/carsandtransportation/agbodybellhousings000http://imageevent.com/publicgallery/carsandtransportation/agbodybellhousings000 regarding factory linkage and bellhousings, covers both 153 tooth and 168 tooth flywheels.
  
  If you use the factory linkage, some things also need to be considered. An aftermarket T-56 can be used with the factory bellhousing/linkage as it has a standard Muncie/Saginaw/Borg Warner bolt pattern, but if you choose to use a Camaro/Firebird-specific transmission an adapter plate is required. There are two that I've seen so far, one is from THE GEAR BOX (Garden City, MI). Their adapter plate allows the use of an LT-1 T-56 on either a standard (Muncie/Saginaw/B.W.) bolt pattern or the slightly rotated (17º to the right) T-5 pattern, which was in the 3rd generation F-Body. It allows the use of an LS-powered F-Body or Viper T-56 to be used.
  
  An extended pilot bearing is also required here.
  
  
  The other adapter plate is from FORTE'S PARTS CONNECTION (Framingham, MA) and allows the use of your factory (Muncie/Saginaw/B.W., NOT T-5) bellhousing with the T-56 from an LS-1 equipped car.
  
  The Gear Box's home page
  Forte's home page

Driveshaft
I haven't really found more than a couple sources for driveshaft length, so you might be best to measure it yourself to double check. I found a measurement for both a G-Body with 7.5" rearend, and an 8.5":

• 7.5: 49¾" inches from the center of the rear u-joint to the tip of the output shaft - LINKhttp://www.darklair.com/T56.htmlhttp://www.darklair.com/T56.html to "MikeD's" page (search the page for '49 3/4')
• 8.5: 47¼" centerline to centerline of the u-joints - LINK to John Bzdel's page (search the page for '47.25')

Crossmember
Aftermarket crossmembers are available to retrofit a T-56 into a G-Body, one of the most well known companies is Crossmembers.com. The part number for their crossmember is RCT56, and it allows you to run the exhaust on both sides of the transmission, unlike the factory crossmember which only has provision on the passenger's side. The site also states that for a '78-'83 car will need PN FE100 (driver's side extension, adds 2 mounting holes), and that '84-'88 cars don't need this extra part. I could be wrong, but I believe I've read of people just drilling through the frame where needed on the driver's side. I've also read of 'Iceman' having a T-56 crossmember (his parts can be found via the main page of this site), but from the list I've seen on the main page only showed one lightweight crossmember (he also sells the extension listed previously for the driver's side).

Good info 😀 I still have to list the bellhousing stuff 8)

True, some headers won't fit. That's one of the downfalls to using mechanical linkage. I may have to go with a different set out here in AZ if they have to be emissions-legal, and if that's the case I have a lot of pondering to do.