L31MaxExpress
I'm Awesome
With a dyno sheet in hand the torque peak/curve would have been evident. If the cam in there peaked 3.5k which would be near perfect for what you're doing and the new peaks at 4.5k you just went the wrong direction for your gearing and your main concern that seems to be towing.
If you factor drivetrain losses for the chassis dyno it wasn't doing terrible for a mild 383.
You can raise the peak and still get more torque in that rpm range. Better headflow generally adds more torque everywhere. A bigger cam often adds torque everywhere beyond the extreme low-end as well.
I like Rhoads variable lifters for this very reason. You can go up a couple of steps in cam and get the low end torque and driveability of the smaller cam but around 3,500-4,000 where the lifters restored to full duration and lift you get the increased power of the larger cam. Rhoads lifters also increase the idle and no load vacuum substantially. My 11:1 383 with 210cc ports has a 218/228 @ 0.050, 110 LSA, .578 lift cam. At 650 rpm it makes 19 in/hg vacuum. At 3,000 rpm with no load it makes 24 in/hg. Throttle response is quick and it has a rapid torque increase just off-idle. Torque peaks is more of a plateau than a peak and it stays within a few ft/lbs of peak from 2,500-4,500 and makes peak hp at 5,700 rpm.
I would love to see a before and after dyno chart.