Last Updated 09/21/06

Installing a Keisler Engineering 5 speed kit into a 1977 C3 with an original 4-speed

I ordered the transmission kit, clutch kit, flywheel, shifter, and new bell housing.  It is attached to a new GM ZZ383 Crate Engine 425HP 12498772.

My C3 already has a 4 speed so nothing needed to be changed.  Keisler has kits to convert automatics to 5 speeds if you plan that sort of conversion.

For details about the kit, visit the Keisler Engineering website or give them a call. 

Keisler Engineering, Inc.
2250 Stock Creek Blvd.
Rockford, Tennessee 37853 USA
Phone: (865) 609-8187
Fax: (865) 609-8287

http://keislerauto.com/

The order and delivery experience experience with Keisler was positive.  The kit arrived earlier than quoted.  All parts seem to be there.  The kit is complete down to the new shift plate for the console and original look shifter. 

Not so easy

This is not a bolt in kit as you may have been led to believe if you read their website information. 

I am a little disappointed with the fit and modifications required to make it work in my 1977 C3 Corvette. 

• Keisler provides a new mount plate for the crossmember.  There are slotted holes but they are not usable in all cases.  I had to cut two slots in order to get my tailshaft aligned parallel to the driveshaft and off the center tunnel.  There is no excuse for this.  The mount needs to take this into account.  I can think of several ways this could be done without requiring the customer to make modifications to the Keisler part.
• You loose your exhaust hanger at the center crossmember.  This is not a good thing if you have stock exhaust.  It keeps the pipe from rattling inside the crossmember.  Again, no excuse.  Keisler should provide one.  One more problem you will have to confront during the installation.  Not a  show stopper.  Just an annoyance and time sink.
• In my case, there still wasn't enough clearance between the yoke, tunnel, and parking brake cable.  I went back to my old rubber transmission mount because it was 1/2 lower.  That drops the tailshaft down.  But that threw the driveshaft angle out.  So back to the new mount so the driveshaft would be straight relative to the tailshaft.  I also bent the parking brake roller to the side to try to gain extra clearance.  It's still to close for comfort in my opinion.
• I ordered everything from the flywheel back including a new bellhousing.  The bellhousing inspection plate does not fit my engine.  I think it is a problem because I have a newer 1 piece rear seal with my ZZ383 crate motor.  They were not aware of this issue.  Support says they only have one inspection cover.  Snips and a bench grinder cured the clearance problem.  Not elegant but functional.

It's a great conversion.  I'd do it again.  Just be aware it will be a little more difficult than advertised.

Getting started

I'm installing a new engine and transmission.  With the engine out, the transmission installation is easier.

The new transmission is about 100 pounds.  The Borg-Warner I removed was 70 pounds.  Take this into account.  What goes back in is a whole lot heavier, especially if you are installing this solo with the car on floor jacks!

  Check - Body Mounts

You are going to need all the clearance you can find between the transmission tunnel and the top of the transmission.  If your body mounts are old, there's good chance they are collapsed and the body is sitting lower on the frame than it should be.  It is time to replace them.  I have a procedure on this site to do this.  My car had new polyurethane mounts installed prior to the transmission installation.

Disassembly

Engine was removed with the bellhousing attached.  You should support the transmission.  The only thing holding it will be the rear mount and driveshaft.  You might want to drain the transmission so you don't make a mess when the yoke is removed.

Remove the shifter connections.

Remove the speedometer cable.

Remove the electrical connections.

Remove the bolts to the rear mounts.  Note that the exhaust hanger is attached to the transmission mount so make sure you remove the bolts holding it.

Pull it out.

Remove the bolts on the rear U-Joint. 

Pull out the drive shaft.

Remove the bolts that attach the shifter to the cross member.  Remove the shifter knob from inside the car.

Remove the shifter from below.  Check the condition of the rubber boot and replace it if damaged.  This is done from inside the car and require removing the console plate.

Preassembly

The bellhousing runout must be checked.  Keisler wants you to check it and document it.  This is a requirement for warranty.  The maximum allowed runout is .005".  Anything greater must be corrected with offset dowel pins.

I assumed my new ZZ383 and new bellhousing would be within specification but they were not.  Mine was .010".  I ordered some .007 offset dowel pins to correct this problem.

It wasn't as easy as I expected but I managed to adjust the maximum runout to .001".

Once the bellhousing alignment is correct, you can install the pilot bearing and clutch.  Install the new roller pilot bearing.  Freeze it then drive it into the crank with a socket about the same size.  Make sure the seal faces toward the transmission.

Test fit the transmission to the engine, clutch, and bellhousing.  It's a TIGHT fit. 

Fill the transmission with 3 quarts of Dextron III / Mercon.  The tailshaft is capped so don't worry about it leaking.

Test shift the transmission per Keisler instructions.  No problems.  Not sure what you have to do if the transmission doesn't shift properly because something is disturbed during transit.  Remove the tailshaft rubber plug before trying to rotate the front shaft.

Assembly

Install the new rear mount plate

Remove the old plate and install the new one on the rear crossmember.  Install the new rubber transmission mount.  The exhaust hanger will NOT work.  The new rear mount position is about 1/2" higher and at least 1" further to the rear.  The exhaust hanger will be in the wrong location and too high.  A new hanger should be part of the Keisler kit in my opinion.  Now I have to figure out some way to keep this pipe from rattling inside the tight tolerance of the tube through the rear crossmember.

Install the driveshaft

Install the driveshaft and install the rear straps to hold it in place.

Lift the transmission into place. 

Lift the transmission and slip the yoke into the tailshaft.  Make sure you remove the rubber plug first.  Don't worry about drips.  I had the recommended 3 quarts of Synthetic Dextron III in mine and nothing spilled.

Once the transmission is in place and supported, loosely install the bolts to hold the transmission to the mount or mount plate on the crossmember.

Support the front of the transmission.  I suspended it with a chain over a 2x4 for a while until the engine was read to go in.  Then I switched to supporting it with a floor jack

Install the engine

This was easier said than done.  Everything is a very tight fit. 

After over an hour of lifting, changing angles, and pushing, the front shaft of the transmission slid into place.  The Corvette's long nose prevented my from installing the engine from the front.  I came in from the side.  If you could install from the front using an engine hoist, the angles work much better.  As you drop the engine, it moves to the rear.  When you do it from the side, as I had to do it, the engine moves to the side as you lower it.

  Tip - Leave the fuel pump off

If I had to do this again, I would install the engine without the fuel pump attached.  With it removed, there's a lot of extra freedom to move the engine front to rear at a lower height.

  Tip - Don't knock the release bearing out of the fork

Careful.  On one occasion the front shaft knocked the clutch release bearing out of the fork.  Make sure you install the bearing properly afterwards.  There are two ways it will install.  One is the wrong way.  This is easy.  The other is the right way.  This will be harder because there are pieces of spring steel that hold it in place on the fork.  These have to be in the slot on the bearing and not behind it.  Keep checking to verify it is still properly seated until the front shaft is inside the clutch splines. 

Keep pushing and wiggling it until there's only about 1/2" of space between the bellhousing and transmission.  That means the front shaft has engaged the pilot bearing.

Bolt the transmission to the bellhousing.  Don't force anything.  It should slide in easily as you tighten the bolts.

Button up the loose ends

Connect speedometer cable using correct gear.  19 tooth gear for 3:73, 17 tooth gear for 3:55.

Connect electrical connections.  The neutral safety switch is located near the end of the tailshaft.  The backup light switch is near the center, on the opposite side of the fill plug.

Check to see how everything fits.

  Alignment Problem

I ran into an alignment problem at this point!  I did not expect such a serious problem.  The tailshaft is longer.  The transmission was obviously very off-center to the drivers side.  That places the yoke back in an area that doesn't have a lot of extra space.  In my installation, the yoke was up against the tunnel and I was out of adjustment on the mount.  You will have to widen the slot on the rear mount plate so you can slide the tailshaft toward the passenger side. 

 

Their instructions were to drill the slot!  This is an outrageous requirement to make a kit work.  This is something that should be handled by the new Keisler mount in the kit.  If this problem occurs and is documented, why not redesign the mount? 

  Correcting the alignment problem

You have to slot the Keisler supplied bracket in order to push the transmission sideways.  Pictures are below.

Reinstall the clutch linkage

No difficulty here.  Just install the pieces and adjust the clutch to specifications for your vehicle.

Install shifter

Easy.  Just remove the left side console panel.  Remove the 4 screws holding the leather boot in place and remove the boot.  Remove the 6 screws holding the rubber boot in place.  Slide the boot to the right and lift out.  Place the shifter through the boot.  Install the two bolts that hold the shifter to the shifter base on the transmission.  The shifter will install on either side of the shifter base.  The proper location is on the  passenger side of the shifter tab.  The slot at the top of the shifter is installed toward the rear.

Reassemble the interior pieces.