I also had a 1975 Chevy Monza with the factory V8 . It also is based on the Vega body with some up dates . This one was a non hatch back . And had the 262 Chevys smallest V8 with a saginaw 4 speed 288 first . And it had a 7 1/2" 293 open rear end . It was stock like this . Latter I installed a bigger cam and 4bbl high rise . Still with no headers and the open rear end this car ran low 15teens . But it had MPH like a high 13teens car . It would not hook well without Posi . And GM left the 4 cyl brake set up on them . One time I could not stop at the end of the 1/4 mile and ended up in part of the corn field !