I paid $385 for my new weber DGV. sounds like alot but that also included dyno tuning of the complete engine. I recommend having your carby at least jetted properly as it makes a huge difference. stops it from running like a pig when cold and gets rid of the flatspots on sudden acceleration. also benefits the fuel economy by and large. you can do it backyard by repeatedly going down a size in jets and taking the car for a drive, as soon as it starts 'pulling' go back up a size in jets.. if there was no noticeable decrease in power on the second last setting then it is probably okay to go back two sizes.
if you are getting the cortina carbies remember they are jetted for a 2ltr engine and also try and get the manual choke ones because alot of the time the old electric choke ones stick closed because the solenoid is farked. and then you rip it off and then the thing is not as good to drive when cold.