Can anybody tell me how to get my speedometer working? I just install a
CA18DET engine and gearboxin my
1200 sedan.

i remember reading in Zoom that apparently the spedo cable and speedo from any ca18 motors will work as well as bulebird cables and speedos. will try to find the article.

what gearbox are you using?
im assuming its the standard 5spd that the motor came with?

The gearbox is 5 speed with electrical speedo sensor. My meter carrys cable. Can I replace the speedo gears in the g/box to work with the original 1200 dash meter ? Or is there a meter that will work in the dash circle?

There are many different speedo drives (different ratios have different coloured gears) from different models that will fit in the CA18 gearbox. I think the early skylines are the best place to get one from. If you can find a Nissan wrecking yard, they might let you try a few different speedo drive units. I recommend doing this, and using a Bluebird (910) speedo cable (It's 300mm longer than the B110/B210 one).

I've considered buying an autometer electronic speedo, and adapting the electronic drive, but it's too expensive to justify.

Chris.