J8I was highly resemble the Soviets' experimental fighter Ye152/Ye152A series! The 1961 twin engines Mig21 for high altitude interception!

J8II wasnothing better besides  a bigger nose housng a bigger radar! Both planes were heavy and very clumsy!

China was 25 years behind the west and 20 years behind the Soviets in 1980s! The J8 waslike copy ad paste with the Soviets blueptrints! China lacking the basic institue of building advanced aircrat like the Soviets' TsAGI (Central Aerodynamic Institue) !   RIP J-8I & J8II brothers!