Headers and or manifolds exhaust exit location

[BigElittleg64]

Truck is a 1964 C10 Long step lowered. Running 1969 350 and 700r4. Engine is located in the rear position and i have done the 1978 crossmember swap. I have the long tube headers and of course they have clearance issues. I am wanting to run the shorty headers and or smoothed Corvette manifolds with the bigger 2.5" collector. I have been reading all of the headers FAQ's and was wondering if I will have issues with the ones that are straight down, will they come in contact with the crossmember or should i be looking for the ones that exit more to the rear.