The C-4 wont explode unless you really abuse it,I had one in a 77 F150 behind a 351 cleveland that I pulled a car trailer with and had no problems,you can find a smallblock C-6 in the late 70s to mid 80s trucks and vans. A regular two barrel carb will bolt where the variable venturi carb was as I done that swap on a 82 F250. There are two different C-4 trans,the car version and the truck. The car trans has the dipstick tube going in the case and on the truck trans the tube screws in the pan,I have allways used the truck trans as I have been told it has heavier clutches and seems to shift firmer that the car version. If you get the two trans togather you will notice the truck versions case is larger than the cars.