I had a similar problem when obtaining cam recommendations from manufacturers. They generally recommended me a cam that seemed to have too much duration for my needs. I would explain that I wanted low end similar to that of the original 1971 smogger L42 350 engine that was generously rated at 270 crank Hp. I explained that I wanted something to just drive around town and would NOT be drag racing. I am keeping the 3.31:1 gears for fuel mileage and comfortable driving. I had the 350 bored 0.030 over with pocket ported S/R Torquer heads, Edelbrock performer Intake, 9.4:1 CR, balanced engine and headers. I had cam recommendations that were over 240 degrees duration at 0.050 and over 0.500 lift at the valve. Comp cams recommended the XE268H as a minimum. I am still undecided between the XE262 and XE268. With the original engine, I could easily shift into 4th gear at 35 mph and car would react fine. If I was making an acceleration run, I would shift at 5000 rpm. Now I am looking to shift at 5500-5700 rpm for a high speed run and yet still retain the ability to comfortably drive around town and shift at 1800-2000 rpm. Maybe this is impossible and I need a smaller cam. Comp cams says either cam will allow me to do this as they will make approx the same torque as stock BELOW 2000 rpm and more torque above it, especially with better heads. However they recommend cams that have rpm ranges that extend beyond 6000 rpm. The XE262 has a range of 1300-5600 and the XE268 1600-5800 rpm.
I remain confused with some of the factory recommendations
I'll pose this question again: For a high acceleration run such as drag racing, when is the best time to shift gears? Slightly before max Hp? That is, if max HP was realized at 5600 rpm, shift at 5500 while the car is still pulling? Comments?
