G'day Stinky,
I went through the cable conversion process a while back:
http://www.fbekholden.com/forum/viewtopic.php?f=25&t=21683&hilit=harv+pedal+cableI used a universal cable conversion kit from Flexible Drive, as I could not get a Mitsubishi L300 cable set up. I figure the Flexible Drive ones will be around a bit longer than the cables from wreckers.
The main drama comes with the original GMH firewall pedal lever, which is attached to the accelerator pedal and pokes through the firewall. This lever only moves some 12mm (from idle to WOT) on an FB/EK Holden… probably similar on an FE/FC. This means that the cable being pulled only moves 12mm too. For many carburetors this is not enough movement to get the carburetor throttle plates fully open. A potential remedy is to extend the firewall lever by welding (or bolting) on some flatbar. There is only so much that the lever can be extended though before the extension clashes with the subframe. As a guide, extending the firewall lever by an extra 40mm will deliver a cable pull of 35mm. This is better than the factory 12mm, but still not a huge movement – the factory single BXOV-1 Stromberg needs about this much pull.
For a longer cable pull, one option is to leave the firewall lever connected to the various levers across the firewall, and connect the cable to the upper cross shaft lever on the passenger’s side of the engine bay. In standard format, the end of the upper cross shaft lever side moves 35mm at the tip. This lever has a lot more room to move in (between the engine and the passenger’s side inner guard), and can be readily extended by welding or bolting on some flatbar. Extend the upper cross shaft lever 100mm will give 50mm of cable travel. Extending 200mm gives 70mm travel, whilst extending 300mm gives 85mm travel.
You can get cute and put a lever on the carb (cable pulls lever, lever pulls carb throttle arm) to give more travel… kinda defeats some of the purpose of running a cable though.
Apologies that the above is a little FB/EK centric, but it may help.
Cheers,
Harv