The 64-65 ball and trunion four speed with the lower gear 3.09 first would be a better choice with the slant six. Plus there cheap and you get t use your current drive shaft. If the car is a stock manual three speed it's a direct bolt on to the back of your cast iron bell housing. All the linkages fork bell crank torque shaft will work. You just need to open up the floor in two places get the correct linkages and your ready to fly.
