1977 to 1990 Full Size Chevrolet Manual Transmission conversion instructions with materials list:
Foreword: GM must have had intentions of a manual transmission option for these cars in the beginning stages of development, as all the appropriate knockouts are there, just waiting to be used.
PLEASE READ THESE INSTRUCTIONS FULLY BEFORE ANY WORK IS DONE. IF YOU ARE NOT MECHANICALLY INCLINED AND USED TO PERFORMING “MODIFICATIONS”, EITHER GET A MORE EXPERIENCED PERSON TO DO IT OR GET THEM TO HELP YOU. I STRONGLY SUGGEST YOU READ THROUGH THE PROCEDURE THOROUGHLY AND UNDERSTAND IT COMPLETELY, BEFORE YOU BEGIN WORK.
Parts needed for the conversion of the ‘77-’90 B-body full size Chevy is as follows:
The changeover can be performed using all factory stock, non-modified parts with the exception of the stock Impala brake pedal which will have to be heated, bent and the tread pad cut down to smaller size.
NOTE: BE ADVISED SOME CHEVROLET MOTORS DO NOT HAVE PROVISIONS FOR MANUAL TRANSMISSIONS. THESE NECESSARY PROVISIONS INCLUDE, BLOCK MOUNTING POINTS FOR THE CLUTCH PIVOT BALL STUD AND THE CRANKSHAFT MUST BE COUNTER BORED TO ACCEPT THE CLUTCH INPUT SHAFT BUSHING. WITHOUT THESE IN PLACE, YOU CANNOT PROCEED WITH THE INSTALLATION. I HAVE READ SOME 305’S DIDN’T HAVE ONE OR BOTH OF THESE NEEDED ITEMS. CHECK THESE AREAS BEFORE GOING ANY FURTHER. THESE AREAS CAN BE IDENTIFIED USING COMMON CHILTON MANUALS, IF THERE IS ANY QUESTION AS TO THEIR LOCATIONS.
Parts List: All of the items can be sourced from any manual transmission 70-81 Camaro and Firebird (1) & 75-79 Nova and GM clones (1).
(1). The pedals only can be used from the Firebird and GM clones, unless they are factory equipped with the small block Chevy engine, then all pieces can be used. There are differences in the bell housings, z-bars, mounting plates and linkage components.
1. Complete clutch linkage set from the second generation Camaro (or suitable other source…read above footnote). This includes; Z-Bar, Frame mounting plate, upper and lower push rod assemblies, including threaded lower adjustment rod and lock nut. You will also need the screw in block pivot ball/stud and the Camaro clutch pedal. The stock Camaro brake pedal can be discarded, as it is not going to be needed.
2. A stock V-8 Chevrolet Bell housing. To my knowledge, only the Monza bell is different. Also the newer style Camaro bells can’t be used due to the angled mounting for the transmission. Stick to the old second generation Camaro style.
3. Manual transmission of your choice. This could be any factory style 3, 4 or 5 speed transmissions. Saginaw transmissions can be used in milder horsepower applications and offer a wider variety of internal ratios. With sensible driving these transmissions work fine. A better choice would be a Borg Warner T-10, especially the one with 2.88 first gear ratio. These were found in late 70’s and early 80’s Camaros.
4. Shifter of your choice. I used a early 80’s “wedgie” style Camaro 4 speed shifter. This worked beautifully with the stock bench seat, although I had to keep the seat the whole way back to allow room enough for shifts to second and fourth. I reversed the shifter arm in the socket to achieve this needed reversed “dogleg bend” to clear the seat. If an aftermarket Hurst shifter is used, several different styles of shifter levers are available to provide just about any odd-bend you may have. Remember to cut the hole in the floor just big enough to clear the mechanism. This leads to a neater, more factory appearing installation and avoids the necessity of the unsightly “Mega Boot”. The factory style pressed metal hump from the donor 2nd gen. Camaro could be used to provide a more finished look. If you are running a Borg-Warner T-10, then you should be able to use the matching Camaro shifter, dust seal, boot and ring right onto the “hump” plate. The use of factory parts further creates a “factory installed” look.
5. Transmission output yoke to suit transmission to be installed. Keep in mind Muncie and Borg Warner transmissions use the large Turbo 400 style yoke, and therefore, must be used. The use of the larger output yoke may require shortening of the driveshaft. Measure accordingly. Make sure you have adequate “slip” distance! If you are replacing a turbo 350 or other small output shaft diameter trans with a Saginaw, your existing driveshaft will most likely work without shortening.
6. New transmission mount to suit transmission. You may need to do some research here to find the right mount with the single stud to match the stock crossmember. Saginaw swaps can simply use the same type of trans mount as a turbo 350. The stock cross member bolted right into the same existing holes in the frame. Since the TH 350 uses a single stud, you may be able to bolt this mount to the Muncie or BW. This is only an assumption; you will have to verify this on your own. Perhaps the stock rear x-member has enough room to drill 2 more slots in it to use the double bolt mount. Again, check and plan accordingly. Install the crossmember.
7. Speedometer bolts right onto manual trans. I encountered no conflicts here. The speedo gear may or may not produce the correct reading, due to a different speedo gear. If it is obvious the speedo is way off, follow a friend out the road and compare readings… add or subtract accordingly. You should get the correct gear to keep things accurate. You wouldn’t want someone else unfamiliar with it driving the car and getting a ticket.
8. Fabricate a locator rod from threaded rod bought from the local Home Depot or hardware store. I believe you need to get 3/8” coarse thread rod. Measure off 12” and grind down the one end to reduce the diameter. Grind off enough material to allow the end of the locator rod to slip into the frame mounting plate slot.
NOTE: You may want to remove the front seat to make things a lot easier to get at. This also keeps things from getting dirty and greased up. Care exercised here will make the end result look like it was meant to be there.
1. Begin by removing stock brake pedal and cross pin. Modify the stock brake pedal by careful heating and bending to spec. Use care when removing pedal as to avoid damaging brake light switch and brake master cylinder push rod. You will also notice the insulated floor padding has a round perforated corresponding “knock out” section. Carefully push it out and clear away the insulation behind. Remove plug in firewall located to the immediate right of the master fuse block. If I remember correctly, it is a knockout plug. If your car has cruise control, there will be soft vacuum lines running thru here that will need to be relocated. Next hang the modified Camaro pedal with the modified stock brake pedal. It’s a good idea to lube the pivot point/bushings at this time! Make sure you re-attach the brake push rod and make sure you re-install the brake light plunger switch. (You do not want to get a ticket, or rear-ended, on your maiden voyage with your new manual transmission!) Feed the upper push rod thru the opening. You may need to fine-tune the lateral location of the rod thru the opening with a few large diameter washers. Install a clutch return spring and hook it to the bracing under the dash. You may want to put some sort of flap or rubber piece around the hole to keep out bugs and water. I never got around to doing this, but I never seen any water leaking in… if the donor Camaro “accordion boot” is in good shape, I can’t see why it wouldn’t work. You may also want to put some sort of bumper or rubber hose section up where the clutch pedal may hit the bracing. On stick optioned cars there is a bumper to prevent noise.
2. Raise the front of the car and support on jackstands high enough to safely remove and install the transmissions. Remove the driver’s side wheel. The rear corner of the inner wheelhouse will have to be trimmed. I used tin snips, but it looked pretty rough. The inner fenders are much tougher than they look. Perhaps an air nibbler or maybe some sort of dremel or small cut-off wheel could be used. The ultimate thing to do, is mark accordingly and remove the wheelhouse and cut on the bench. Refer to the drawing for proper cutting. Thread the 12” locator rod into the clutch ball-mounting hole into the side of the block. This projects a line across to the exact location the end of the Z-bar. Place the slot of the factory Camaro frame mount plate over the end of the rod and transfer the locations of the three holes to the big cars frame. You could use transfer punches or spray paint to help mark the proper hole locations. The plate will need to bent/rotated slightly, counter-clockwise, looking down from the top. This can be achieved by removing the plate, heating and bending the appropriate amount in the bench vice. Reinstall the plate and check for fit.
With the plate mounted securely, remove the locator rod and install the factory style pivot ball stud in the block. You will be using the rear hole, right above the oil filter boss, as the front is used for Chevy II applications only. Move on the next step.
3. Remove the factory exhaust system and put aside. I had no problems in my instance. I used the stock iron manifolds and single exhaust “Y” pipe. Everything bolts back together fine, including the converter, etc. I would have to speculate about the fitment of tubular headers. I have used Camaro/Nova headers on full sized boxy Chevy before, and they bolt right up, but then I was using a TH350 automatic…
4. Remove the factory automatic transmission, don’t forget to remove the kickdown cable and dip stick tube, as well as unhooking the speedo cable. Remove the factory flex plate and install an input shaft bushing in the end of the crank. At this point measure back from the back mounting surface of the motor to determine where the hole in the floor board needs to be to accommodate the shifter mechanism. My car required 24” to work, your car may be different. You may want to bolt the bell to the trans and put the shifter on temporarily to get an exact measurement. Measure twice and cut once. I cut a smaller hole in the floor and ended up fine-tuning it with tin snips later. This produced beautiful results, which looked entirely factory.
5. Depending on your choice of flywheel/clutch size, you may have to change the starter. There are 2 different flex plate/flywheel diameters so have your man at the parts store cross reference your existing starter to one from the car your manual is coming from. He may need to know the ring gear diameter or number of teeth. These are the best ways to ID what you have. Buy the appropriate items beforehand to make the transition an easy, one weekend affair.
6. Install the flywheel and clutch assembly. It’s a good idea to pre-install the shifter and shifter rods while the transmission is out, I did mine on the workbench. Adjust the rods using the gauge rod, as per the manufacturers instructions. Install the transmission and shifter, less handle, for ease of installation. Carefully raise the trans in place with a floor jack. As it pivots up into place check for interference between the shifter linkage rods and the transmission tunnel. I had to get out the big mallet (BFH) and “adjust” the tunnel about 1/8th of an inch for the needed clearance. Also check for interference with your hole for the shifter. Trim and modify as necessary. Make sure you have at least ¼” clearance between moving parts to avoid rattles.
7. Install the z-bar by sliding the end onto the block stud and lowering the bar stud into the slot on the frame plate. A critical area here to look at is to make sure the z-bar does not rub on the metal brake lines that run down the top of the frame rail in this area. Since this bar is basically ball pivoted at both ends, one could raise the frame end of the z-bar if you had to clear any possible interference. I kept about ¼ inch distance between my parts and had a friend watch during full travel movement to assure there was no rubbing throughout the entire range of motion.
8. Connect the linkage rod from the bell crank to the shifter fork. Adjust as you would any other factory clutch. Refer to shop manual if you are unfamiliar with this operation. Look at a (2nd Gen.) Camaro or Nova (boxy 75-80 style) book to get the directions/detail views. Don’t forget to add a clutch return spring from the fork towards the front of the car. The illustration in the book will show you exactly how it needs to be. Check for proper engagement and release of clutch.
9. Install the crossmember at this time, keeping in mind the mount as mentioned above.
10. Re-install the driveshaft. If you kept the Saginaw style trans., it should bolt up fine. Check to make sure you have enough slip in the yoke. The generally accepted slip distance is about ¾ inch. If you are unfamiliar with how to do this, get a friend to show you how. With the driveshaft o.k. And correctly installed, you can proceed with the next step.
11. Re-install the exhaust system and make sure there are no leaks. Replace any bad sections if necessary.
12. Test drive in a safe area to assure proper operation. Recheck all your fasteners. You are done.
Once you are satisfied all is well, take it for a test run. The car should behave like a completely different animal now. Depending upon your choice of transmission and rear end gearing, the car should be very responsive. You will also quickly begin to notice car guys doing double takes at the sound of a clutch coming from such an unlikely source.
Above all enjoy your work!!
Some last words:
The above mentioned process worked for me. My car was an ’85 model and I am assuming the last few years also had the appropriate provisions already in place to complete the job. You should check your car beforehand to assure everything is good to go. I cannot and will not be held responsible for any accident, injury or damages resulting from installing the manual transmission. It all fit together fine using the parts I had… any deviation from this may result in some problems, which you will have to figure out on your own. You will have to figure out the reverse lights on your own too, as different transmissions have different ways of turning on the reverse lights.. BW in Camaros have some sort of big linkage set-up that actually rotates the rear of the steering column sleeve to get the lights to work. Other transmissions have an actual plunger switch screwed into the case that work when the reverse lever is used from the shifter above. This will have to be resolved on a case-by-case basis. I simply put my reverse lights on a separate switch and left it at that.
I’m sure others will come up with different combos or slightly different methods of achieving the same ends. Above all be patient, and through in the installation. I can’t stress enough to work under the car safely and to have an experienced helper with you, if you feel uncomfortable with any part of this operation. I have performed many non-stock swaps and feel comfortable with the heating and bending operation.
It is also my suspicion that the clutch installation should work on 4 door sedans, 2 door sedans and wagons, as they all seem to have used the same firewall.