I added a solenoid to my modified 29 rdstr. with a Miller O/H "B" motor. I mounted the starter button in the floorboard under the carpet between the peddles. Couldn't be seen except for a slight bulge in the carpet & could use the foot as orig. to start it. NO EXTRA HOLES in the dash rail. Connected with bayonet connector in case the floor bds. had to be removed. Worked great. Sold the car last yr., it's now in Canada.