First off, sorry for not having pictures, but the forum will not currently let me upload them.
But here we go; since I haven't seen a thread on this, here's a little step by step on conquering on of the many hurdles that come with an engine swap- getting a Accord cable operated speedometer to work with a electronic signal Integra/ B-Series Speedometer. It's not as bad as it could be, and a little bit of effort can make this project a breeze.
You will need:
Our stock A20 Speedometer Housing
A speedometer from a B-Series Transmission
A heat gun
Prolly a fridge/freezer. Or just something nice and cold.
A Hydraulic Press
...and a 10mm socket. (You're working on a Honda after all)
I happened to have had two of each speedometer, which was extremely useful, since breaking stuff is something I do way too often.
So starting off you need to pull the speedometers, located in the back of the transmission closest to the firewall, the B Series is "easy", just unplug one thing, and then take out the bolt that connects the assembly to the Transmission loosen those other two bolts, and with a little help from a prybar will have this one out. The Accord is the same way, but comes with those agonizingly tiny power steering line hose lines that need to come off (and treat them with care! The point is too keep using those!)
Now that they're both out finish taking the housings apart. Not tough, and the A20 seals are most likely fine. To take out that pump gear, just flip it upside down and spin the speedo gear and it should fall out, then- back up top- you should be able to slide out that little pin with a pick/fingernails if you've got em.
Now you have both rods & gears side by side, and its easy to tell the differences, the A20 has a taller rod, and a shorter gear. This will technically fit into the B series trans as is! BUT it makes a whirring noise while spinning the diff, which means you'd eventually shred something, and that's no good! So to fix this issue, you need the B-Series gear to be mounted on the A-Series rod. Be sure to make a note of how far up the B-series gear sits on it's rod, as that will be the measuring stick that will be important for the final placement once it's on the other rod.
This is where heat comes in handy! Cook the crap out of the B series gear, put in a press, and push that rod out! Just make sure the gear (which is, admittedly, made of super strong stuff) stays in shape. And now do the same thing to the A20 speedo, lots of heat, a lot of pressure, and it'll come apart.
Once the A20 Rod has cooled a little, put it in the freezer and be as patient as you want to be. In the meantime, totally toast that B series gear in heat, then, once you're done tapping your foot, put the gear head down in the press and push that rod into it! It is shouldered, so it'll come to a stop eventually, but you may want to check that original measurement you took with the B-Series rod.
Now slide the B18 Gear/A20 Rod combo back into the A20 Speedo, and rebuild it! Easy! You're done!
BUT BEFORE YOU BOLT IT IN; The housing on these A20s is WEAK. Make sure that bolt standoff/leg/thing is FLUSH ONTO THE TRANS BEFORE BOLTING IT IN, they crack off super easy, and I broke mine and have to go to the junkyard -which isn't necessarily punishment, but dangit. Just bop it with a rubber mallet/deadblow/a shoe/who knows what, to seat it, then bolt it down.
And as far as I know, that's it! I have NOT road tested this, but can't imagine why this won't give you some sort of speedometer. So who knows, maybe 80 will equal 25 all said and done, but it's better than doing wiring IMO.