These are upscaled version of Alfonso X Morales Shuttle Solid Rocket Boosters and External Tank in 1:96 scale.
The SRB are based on his srbstack1A.pdf and the tank on etsts3.pdf. The originals are in 1:144 scale and available together with loads of other great models at axmpaperspacescalemodels.com.
Both kits include build notes from my own build.