I have seen the manual sun roof installed on my ex BIL 78 Monte. That car went like hell for two barrel, pretty sure it was a 350 with the 2GC carb. I remember a classmate had a red T-Type, remember it being in the school shop puffing black smoke. Maybe it was still a carbed version? He was friends with Jason who's family had a mechanic's shop. They ran 455's in late 70's/80's Cutlass because they got them so cheap,$150 and threw nitrous on them! Also had a 68 Firebird with a 400. They knew GM's otherwise I would have never known about the T-Type.