1976 Ford Maverick engine cuts out at higher rpm's

1976 Ford Maverick mileage: 150,000. I had a 6 cylinder put a (89) 302 in car.Holley carburetor and fuel pump. The engine will idle fine at mid to high rpm's, the engine starts cutting out like there’s a rev limiter in the ignition system, which is stock.The engine has 10 half to 1 compression, larger then factory cam.I was told it is many different problems!Fuel system, ignition system or valve train.Any input you can add could be a big help to me