Since I'm getting started back on my car I've been fiddling with Engine Analyzer, trying to decide what I'm doing with the car. I'm familiar with the program, and it is pretty close if the info put in is accurate. Right now my target is about 300lbs/300hp, damn powerful and very well mannered with a bit of chop to the exhaust. This may change by this afternoon. The base for this combo is Autolite 4100, Performer RPM or Weiand, a set of professionally ported 351W heads, 1.84/1.5, Hooker 1 5/8, 2 inch duals. I am looking at Comp Cams 268H, 270H and the XE250H. All come close enough to the target 300/300. My cruising RPM is around 2000RPM, the XE250H has the best low end torque. XE250 is 235lbs@2000RPM, 268H is @2500, 270H is @2700. My question is do I want the torque at my cruising speed or will I get better mileage with the larger cam because it breathes more freely? Stock cam gets ~24MPG as it sits now. Since I get about the same HP with all three and better tq with the XE250H, I'm leaning towards the smaller cam. The odd bit is I get nearly the same numbers with better low end with a stock 351 cam. I am not ruling that one out, but I imagine my mileage would suffer with a truck cam.
For whatever it's worth, I loved the way my old 302 behaved with the 268H. Had a mildly cammy idle and respectable power on tap at just about any RPM. With a 2500 stall it was just perfect for a driver. Now I will say I averaged 14 MPG, but that was mixed city/highway driving, with a Holley 600 DP, air conditioning, power steering and let's just say my foot isn't really energy efficient to begin with.
