Well, it all depends on what RPM you want to make the torque. For a heavy hauler, I assume you will be operating below 3600rpm so the exhaust system should be designed for that. Stock exhaust manifolds, rams horn or whtever, are usually designed to fit the engine compartment, period. I seem to recall that rams horns are popular becaues they came out on Corvettes but they are not particularly designed for torque. For the relatively low speed application you need equal length 4 tube or tri-y tubes about 36" long and no larger than 1 1/2". Not sexy but that's what you need. The 24" x 2 1/4" headers you see advertised come on great above 5000rpm but I doubt you will be operation your hauler there much. A 180deg 4bbl manifold w/ 650cfm vacuum secondary carb is also great for below 3600 rpm torque as opposed to the more sexy Victor 360deg manifold w/1000cfm Dominator.
It's simply physics and you can't fool it. Engines are all compromise and for your application make it long and skinny!
[ June 14, 2002: Message edited by: firstname.lastname@example.org ]</p>