what voltage regulator is correct for a 69 shelby gt350 convertible,automatic,no AC...build sheet shows a 4B alternator(which is a 42 amp),battery is AB code which group 24...so does it use silver or yellow voltage regulator...car currently has an original silver (writing) cover,but cant say its the original one(car only has 34,000 miles and is mostly all original...paint,interior,top,hoses,plug wires,battery cables,etc.)...thx keith