Re- shell using non gti body

[TACHYON 0]

My project is to re build my 1.9 1987 rotten and robbed out 1.9 gti into a good 1.1 bodyshell .  Before I start I want to gather some parts to keep it a rolling shell I'm wondering which rear beam to look for as my 1.9 Gti basket case donor is without one at all and the rolling 1.1 shell I have to rebuild with is on drums. Is there an interchange list anywhere. 
 Not necessarily  looking for a full on race spec  I'd like to be able to compete in local rally  events but cost is part of the criteria.  I do have full workshop facilities. 

[TACHYON 0]

I just realised this is not really the right place to post - yet but it will be soon