C8 progress in Texas

David DeWeese · #1 16-03-09, 07:06

Hi,
Finally had a weekend to devote to the C8. Put the time to good use by test-fitting my 235 and a transmission to make sure everything was OK before painting the frame.
Both my donor 4-speed crash boxes turned out to be worn completely out, so resorted to Plan B:
Installed a six cylinder bellhousing from a '60 through '62 Chev truck which has the clutch fork exiting the right-hand side. Now I can use my stock C8 clutch linkage with a bellhousing that accepts the later model GM manual transmissions. Made up a couple of adapters to mount it so not to modify the original C8 crossmember.
Was then able to install a General Motors SM 420 4-speed transmission. First is the ultra-low "granny" gear that I will probably never use, but it now gives me three synchronized foreward gears to work with.
Next weekend I will tear it all back apart to prepare the frame for paint!

Regards, David

Bob Carriere · #2 16-03-09, 17:13

HI David

Do you happen to have the part number for that particular 1960 / 62 bell housing.....

I had considered the same arrangement with a C15A....but.... the modern 4 speed tranny and bellhousing left too little room between the transfer case and the tranny to properly connect with a short driveshaft. Moving the T case bad was not an option I wanted to exercise.

Fortunately for you the C8 lends itself to the conversion you did.

Bob C.

David DeWeese · #3 17-03-09, 06:42

Hi Bob,
The bellhousing is a used one I pulled out of a 1960 Chev 1/2 ton. It had a hydraulic slave cylinder mounted to the right hand side. Had one of the 3-speed column shift transmissions behind it. Uses a longer clutch fork also.
A friend has a factory parts manual for this model, so I'll try to get parts numbers for you.
Thanks, David

maple_leaf_eh · #4 17-03-09, 15:21

I wouldn't expect too many North American vehicles have clutching parts coming out the right side. All our vehicles are left-seat drive. Why would Detroit choose to put it on the right at all? Column shifter linkages ... ?

David DeWeese · #5 17-03-09, 15:45

Hi Terry,
Was wondering the same thing myself. The earlier GM trucks had the same transmission and column shift linkage, but kept the left hand clutch fork location. Since they went to the hydraulic slave cylinder that year, maybe they were concerned about exhaust temperatures.
Thanks, David

Bob Carriere · #6 17-03-09, 16:54

HI Terry / David

The change over was common in North America in the early sixties and I believe originated with the necessity/simplification of operating a clutch system for van type with a semi cabover condfiguration. Brake pedals had already changed over a decade before from solid linkage through the floor to a firewall mounted pedal attched directly to the master cylinder in the engine compartment.

The simplicity (until you have to bleed the darn system) of the hydraulic clutch linkage, allowed them to instal it on the right hand side. Once configured for vans the same concept was kept for pick up trucks.... not sure about the heavier Chev/GMC model. With the advant of automatic and electronically controlled transmission.... mechanical linkages are a thing of the past.

I need the part # to see if I can track one in our neighbourhood for possible future use....

BooBee

David DeWeese · #7 22-03-09, 04:47

Bob,
The factory parts list I spoke of last weekend still hasn't surfaced yet. Will casting numbers do? Found them today under the transmission when I pulled it. Forgot to write them down, but will get them if they will work for you.

Got the frame painted today and motor went in for good. Used the Gillispie paint that worked well for me in the past. Got four gallons for $100 with no haz-mat fees or shipping by picking the paint up directly from Rapco. They are only a little over an hour away from me, plus love to go there and browse all their neat stuff in the yard.
What do you guys think about the color?
Thanks, David