Is ths car stuttering riht off launch or while on the transbrake?
We had found electrical interferrance on the main MSD wire, Too close to the coil wire or coil.
If it stutters on launch and you are not running a jet extension kit, then try raising the float level in the carb a bit and see if the condition changes.
other than that, make sure your MSD wire is not being shared with other components like the trans brake etc.
Also
Run a seperate ground to the head for your MSD