Im in the process of building a project car, FC3S automatic. Im going to do a manual conversion with a LS1 and T56. Will th egearing be ok in the Auto rear end? or would it be best to change out rear ends from a manual?

 

the gear ratio is fine... the strength of the gears is the problem. NA rear ends are not as strong as turbo rear ends and if you don't drive gently it will probably break