It can be done and these cars with V8s rage . The biggest problem is the cars rear end is weak . I do think that the 1975 Vega / Astre can use the Chevy monza 7 1/2 rear end that is slight step up but still not to strong . A friend had a 1972 Vega with a Don hardy V8 kit . He ran a high mile 1965 327 with a 350HP set up and a TH400 . Also a 12bolt from a 1966 Chevy II with a 355 Posi . That car ran 13.26 with street tires . And we drove the car 60 miles to the track to . This is also a car I would like to build .