The Gsxr 1000's engine was just 15 mm taller than the Gsxr 750's

Amazingly, the new Suzuki Gsxr 1000's engine was just 15 mm taller than the Gsxr 750's and because the bore was only Imm larger (at 73 mm), the engine was no wider. Careful attention to component weights - the pistons and connecting rods were lighter than the Gsxr 750's - kept the overall weight in check.
In all, the Gsxr 1000 was a hugely potent yet comparatively tiny engine.