Can someone please give me information on these boxes;
What theyre like to drive daily?
Nowhere near as nice as the Toyota box.
Only 3 speed so whats it like on motorway?
Get used to revs, or fit a Gear Vendor O/D and empty your wallet
Can you use the lockup switch?
Doesnt' have one - unless you go for the weaker full auto or find an aftermarket lock-up option (rare).
Direct replacment for the BL setup im told although need to use my existing bellhousing, What power will they take?
It fits in the hole with some gentle persuasion, thats it! You need new prop/adapter, crossmember mount, speed sensor adapter, cooling fab and shifter mech mods. The power it will take will be based on how it's been built. A manual valve body TH400 will take more than an auto one ( This was the case when I had one anyway, could have come on since then)
Will my pi3200 histall work ok with one?
Nope. It's custom fit.
Is it true you can just stick it in Drive, you have to manually use the gears?
As mentioned, they come in both manual and auto valve body formats. One will give you a big arm, the other won't.
Do yourself a favour and listen to JP. If you want to keep this as a road car with the odd drag here and there, then put a manual in it. At the power you're at you WILL be here again if you stick with a modified A340E box. Turbo 400's, glides, 4L80E's lean more to the dedicated drag enthusiast, and although cheaper than a lot of other options out there, they are still more expensive do to properly than a 6 speed conversion.