I run a set of the hedman 79250 2x BB truck header. (same as swap header from Bouchillon)

they look exactly like the top pic of the 79256 (which would be ceramic coat?)

mine tuck up in the frame and do not hang below it.. the 1 collector bolt is the only thing below frame rail.

for a 4x4 the tubes have to give room for the diff housing/shaft to move up/down.

B-body headers do fit in a truck chassis with a little clearance cut on the upper frame rail. they will hang below frame rail IIRC.

I don't think they will work on a 4x4 chassis due to diff/shaft clearance.

I have both hedman sets for a sb truck chassis 2x & 4x4
79080 sb 2x
79171 sb 4x4
79250 bb 2x

IMHO. hedman is the best fit for the price.