1969 Valiant Signet questions

Looking at a couple different cars to build into low buck street/strip car and i stumbled across a '69 Valiant Signet but know nothing about them. It seems to be the lightest of the A bodies. So i've got a couple questions, and I'm open to hearing anyones opinion on these cars. Its a slant 6 auto right now. Are there any known issues with this platform? Will big blocks fit in them? What most likely will the trans and rearend be? Anyone on here race one?
Thanks in advance