When converting a 1964 Mercury Comet to the V8, what else needs to be changed on the car to accommodate the V8?

Question:

l am in the process of restoring a 1964 Mercury Comet. The car has the original six cylinder engine that I plan to replace with a small block Ford V-8. All six-cylinder models of this vintage had four lugs for each wheel while the eight-cylinder models had five lugs. Will it be necessary for me to replace the four lug parts with the five lug parts in order to handle the extra weight of the V-8? What other changes, if any, will I need to make? I have a '64 Comet V-8 parts car, but don’t want to make any changes that aren’t required.

Answer:

My intuition tells me the extra weight of the V-8 does not by itself necessitate the spindles and axles be changed, because there is not much difference in weight between the six (particularly the larger six) and the V-8. There are, however, a number of other differences between the six-cylinder and eight-cylinder Comets that do, in my Opinion, require you to change the parts from your V-8 parts car. The axles and spindles are different and should be swapped, the rims are obviously different to accommodate the extra lugs, the front springs are heavier, and the brake set-ups on all four wheels are larger. Also keep in mind that both the transmission and differential were different for V-8 models and the radiator was considerably larger as well. And finally, the front wheel alignment specifications were slightly different for V-8 models (the toe-out specification for the outer wheel on turns is changed from 20% degrees to 18% degrees.)