Boy do I have a good one here for you all. I've been reading up on these W-1's like crazy and I think I have something either slightly unique, or totally wrong!

https://goo.gl/photos/QVMgBRckhKUU9cNd7
https://goo.gl/photos/EHjUALgQwjSXCTrC7


So my all-original Canadian '48 3/4t has a W-1 on it, with the tag #839987. No problem, every resource online says it's a 574s and it doesn't have the throttle-choke linkage that would make it a '49 684s. However, take a look at the accelerator pump. It is a long flat shaft, without the spring cup on the bottom, which looks mysteriously like the piston out of the '49! When I opened it up, the spring was BELOW the piston, not above it. The cork ring at the lid makes me think that a spring should not come in contact with it, therefore it should be below the piston.

https://goo.gl/photos/pWm4dqSeg6yUCRKo8
https://goo.gl/photos/KdNBcSuS2AqHFPBx6

I can't say that this is the original carb, but nothing else on the truck has been touched, so it is hard to imagine that it was changed.

Here are my thoughts, and I hope you will chime in with yours; This is either a different carb setup than anyone has seen, or someone has put the wrong piston in the pump.

And yes, before you ask, I have spoken with Carb-King Jon and he said look to the sleeve length in the pump shaft, which as you can see is full depth and I believe indicating a 574s body?

Has anyone seen anything like this? Anyone got some pics they want to swap? A 574s would be so much cheaper to get a kit for!

More Pics: https://goo.gl/photos/u9BGyxYvxu92nVqp6

Thanks everyone

1948 Chevy Thriftmaster 3/4-Ton
Poncho "farming" in Ontario
Starting in the DITY
Continuing in the Project Journals
More images

There are only 10 types of people in this world, those who can read binary and those who can't.