dazza67

Hey Folks.
I am wanting to build a close ratio gearbox for a car we are racing.
What I am trying to achieve is using the ratios from several different boxes to create the ratio set I want, as well as lowering the over all diff ratio for a lower top speed.
Currently the gear box i have is an EHV, the ratios are very wide and we only use 3rd and 4th.
my aim would be a 4.11 diff, a 0.889 top from the DJA, a 1.029 4th from a DRE, and a mix and match of ratios from other boxes to achieve a close ratio set.
My delmer is I don't know what parts can interchange with what, I assume that 1st and 2nd are fixed ratios, and 3rd and 4th are fixed so can only be changed as pairs (1st and 2nd from one box, 3rd and 4th from another) and I dont know if there were different gearboxes where parts from one wont fit another, the diff is an example where the diff might have a larger crown wheel and pinion in one box and a smaller CW&P in another.
Hope you folks might shed some light. Cheers Daz