ok im an old member but forgot my password

so joined up again
ive searched and was wondering is there any problems I will strike fitting a a12 with weber etc into my wagon its currently an a10 and three on the tree haha.I understand I cant put anything bigger in there then I will have to fabricate mounts etc.So I just want to put a a12 in there and a 4 speed or 5 speed if I can find one cheap enough slam it on hubbies whitewalls and cruise it
cheers in advance