Lugging in high gear at 45 mph will not be an issue. I have an 84 K10 with SM 465(high is direct) and 2.73(yes 2.73 not 3.73)axle ratio. Motor is a 305 bent 8 with almost 200k miles on it. This motor pulls just fine in high at 45mph and it doesn't have near the low end torque that the 292 does.
