I agree you lose the starter retard.One thing to add. make sure you run a ground cable from the battery to the motor.
In my cars I run a ground cable from the battery forward to a stud in the roll cage usually at the A bar near the dash. From there to both heads. Yes both . An old timer said it's the added short point for insuring a good ground for the plugs. from the dash stud ground is also where I run my MSD ground.