Mk1 Cortina with sr20 or ca18

Hey guys
I have a mk1 2 door I'm looking to drop a sr or a ca in
Just got a couple of questions
1) is this still possible? Have spoken to one engineer he said still all good but would like to be certain anyone have any engineers numbers that I could have to get abit more info I'm in qld by the way
2) I understand most of the fabricating that is involved but just a couple of queries can I leave the standard clutch and brake cylinders in and will they be clear, if not what's my options also radiators what do other guys use and what thermo fans, fuel tanks anyone know makes custom ones, and lastly what's everyone doing with there gauges anyone bought gps speedos from speed hut or what what's everyone using to get engineers certs for them
3) anyone using standard seats if so how they handling it or are they just to unsupportive
Any other sneaky info would be greatly appreciated