340 Intake manifold recommendations

I have swapped from an air gap manifold to a victor 340 on my 410 but have also swapped to a slightly larger cam ( howards hyd roller custom 238/242 610 lift on a 112 l/seperation and from edelbrock slightly ported heads to trick flow heads.
I have lost low end hp on the chassis dyno but pulled 35 hp on the top end to 425 rwhp. After studying the dyno sheets I noticed the bottom end were it had lost torque it was lean and when the air fuel ratio recovered it rocketed past the old graph. I felt that it was not fully warm when he did the run and since I have gone up jet sizes on the primaries. On the road it does not feel any loss of torque as if you hit the throttle in second gear at about 2ooo rpm it goes sideways with wheelspin straight to about 6500 rpm. ( five speed manual TKO600) I have also noticed if you do the same when it is not fully warmed up it just falls on its face until the revs come up. When you have a 410 properly tuned how much bottom end torque do you need in an A body weighing 2900 lbs with driver. My car an Aussie VJ Valiant Charger has gone 11.4 with the old set up so expect the new set up to go low elevens