Home » » GMC twin 6... single block, 4 heads, 56 head bolts, 2 carbs, and 702 cu in. Also, with modern easy bolt ons, 425 hp at 4800rpm, but 630 ft lbs at 1800rpm. Made between 1960 and 1965

GMC twin 6... single block, 4 heads, 56 head bolts, 2 carbs, and 702 cu in. Also, with modern easy bolt ons, 425 hp at 4800rpm, but 630 ft lbs at 1800rpm. Made between 1960 and 1965