Ivan, Clifford has what are best described as drag racing headers that have long primary tubes and both collectors run down the left side of the engine next to the bellhousing area. They also offer a Street Rod set with shorter primary tubes and the collector flanges are about at the oil pan gasket level. These make it easy to run the rear set of tubes into an exhaust system along the left side of the car and the front set can be fitted with an exhaust pipe set up to cross under the oil pan and run down the right side of the car. You won't always be able to cross under the pan in every vehicle due to crossmembers and steering linkages so these won't work on everything you'd like to put them on.
I'd recommend checking their on line catalog to see the difference in what they offer and see what works in your truck. The street rod headers work well for what they are desigend for but ar not as efficient as their drag headers. One look at the variety of tube lengths and shapes of the street rod header set will make that clear.
I mention the Clifford headers as they are one of the few who offer choices for Inline Chevy tube headers. I'm running a set on a 250 in a 37 Chevy and the quality is excellent compared to most of the other ready to wear tubular headers.
Mike
