when doing a booster conversion on a 1200,we used an adapter from an early lancer,which fits on the firewall studs,& allows you to fit a 4 stud booster without drilling the firewall.i used the galant booster,which was very small,but had to machine the end of the sunny master cylinder to fit.the 180b booster is smaller & you probably wont have to machine the end of the cylinder.to fit to the pedal,i got a 120y end,which is very long,drilled a hole half way along it,then cut off the excess.you could probably do the same with the sunny end.this was in a car with 200b discs & calipers,& needed a booster.i also had the adaptor cut shorter for clearance on the strut tower,but this could be illegal for a street registered car.the person who cut & shut the adaptor was apprentice of the year in welding,so i wasn't worried about this,& it was in a 2e club car anyway.that car is still being raced 10 years later with the same brake booster & adaptor,so i was right about the welding.

i think ill be at the wreakers this weekend looking for one

I know for sure that the small 180b booster fits. The reason why I say small is, from memory there are two different sizes.
You might be able to run a slightly larger diameter booster, but you would be limited by the closeness of the wheel well/inner guard, what ever you call it.
I run a 7/8 Master cylinder on a 180B booster and it works just great.

Good luck with your choice.

can anyone tell me if a sunny break booster and master cyclinder will fit a 1200 sedan. I,m fitting the sunny disks and 180B drums but I don't know if the booster will fit Its alot bigger than the 180B ones