’73 record-double carburetor?………..help!!!!

Hello I’m new here, but maybe you can help me.I’m driving a ’73 record-1,7l. because the driving performance is anything but a record suspect I would like to know if it would somehow be possible to help my second best piece to achieve a bit more performance. since I want to let him run this year on h-marks are things like motörchen out and motor pure not possible:-( there are companies that have such a thing or have someone like that–what costs something–what brings-gi bts except weber and solex still other double carburettor for opel???questions about questions how much can I actually pack on it without having to install on brakes etc. I am very grateful for every tip any help!!!!! oh how difficult is it to connect a speedometer ???have one of nem gt and would like to have it with me in-possible?? with best greetings jürsche