[GORDON STREETER]

Al most cars will alter between max and minimum travel but it's unusual to actually get full movement especially on a race car with stiff springs and shocks. Incidentally I used 600 lb front springs on the Anglia.
Unless the design is sophisticated in the first place and presumably you want to keep it how it was made, as long as every thing is in order the only way to stop it is to limit the movement .
Alternatively with the springs removed and the car on a trolley jack or a wheel free ramp it can be possible to reshape/redesign the steering arms to limit bump/rebound.
Most road saloon based race cars have lowered suspension that can cause problems because the steering angles were not designed to be run in that position.
I don't know what type of suspension you have on your car but when it's at its loaded static ride height what angle are the lower arms in relationship to the ground ?