A neighbor of mine in the 1970's used to rebuild these. Jim Wellington used to own Rennsport Werk in Campbell or maybe Santa Clara. I believe he now lives not too far from the address in the ad.
I remember him giving me a black T-shirt around 1977 that said "Real Carreras have 4 cams". Wish I still had it but likely wouldn't fit these days.
Mark
'80 SC