According to the info I have, NOT SO. The 5.0 H.O. Ford engine adds less that 100 pounds to the total weight of the car. Easily handled by the suspension. The conversion kit also sets the V-8 as far back in the engine bay as possible to retain the vehicle balance. Check out grannysspeedshop.com for yourself & see some of the pictures. The V-8 actually looks kinda SMALL in the engine bay.