working on bored out 235(so its about 242) on a 58 chevy )and i am getting alot of conflicting info about exhaust size. we talked to clifford performance and obviously they recommend their headers which are 2 1/4 in. as opposed to what we had originally designed -- using fentons, which was 2 1/2 in. THe guy we talked to was saying that if too much back pressure is eliminated the torque will suffer because quote" backpressure is good for low end torque but is bad for high end horsepower"??????? just dont get this. why would more force working against the piston on the exhaust stroke creat more torque? What am i to do? Is clifford just trying to get me to buy their headers, which i might add are total:$414.00 with the coating, whereas say hot rods of norco can gove me ceramic coated pair for $219.00. And what size exhaust do i go with? not to mention the problem of fitting on intake and exhaust maifolds ---clifford said that basically their exhaust headers are the only ones that wold fit with their manifold---is this true? cause it sure is expensive.
thanks