Originally when built mine had a small block v8, ps, AC. Some owner before me had converted it to a 454 big block, kept the ps and AC (I don't believe AC was an option on BB Chevelle SS's). I blew the 454 after a couple of years, it was getting around 7MPG. Installed a shorty PB booster and the ZZ502 with serpentine belt and accy package, had an AC company connect the old system to the new compressor. It makes you feel like a *BADASS* driving around. The dual high flow exhaust, cowl induction and ZZ502 factory cam make it sound like a race car. I don't drive it much anymore. I hope to get it out this summer.