new v'er wrote:
Mr. Mopar
I just picked up a set of Doug Thorley tri ys. I have the 360 small block.
I was planning on using a 2.5 inch dual system with crossover. I'm considering Flowmaster, Dynaflo or Thrush mufflers.
I heard that its bad for valves to keep the backpressure too low. Would you know if this proposed system is efficient without causing engine trouble?
Also headers radiate more heat than the cast manifold. Did you have to shield or protect engine components, or the dog house?
Running bare (or no) headers is the usual cause of "back pressure" problems which is typically a case of cold air hitting the hot exhaust valves and warping or breaking them.
Low back pressure can also be called exhaust scavenging which is good. Large pipes and a crossover are important to a efficient exhaust system and your set-up is exactly what i intend to go with.
Yes, higher heat is a problem. I'm planning, at a minimum, to insulate the starter and sparkplug wires. I'm considering a friend's idea, which is to put in ductwork and a fan to pull hot air out of the top of the engine compartment. He says his setup made the engine run better and seemed to improve power and economy.
