Camshaft usage help for a 400 cid.
 

Here are the results of gas speed analysis in terms of the rpm of peak torque and HP for different factory cam’s when used with 67 and up D port heads ( 4 bbl carb ) and the change when a true 1.65 ratio rocker is exchanged from the stock 1.50.

067 cam
Peak TQ. 2980. Peak HP 4530

068 cam
Peak TQ 3260. Peak HP 4790

744 cam
Peak TQ 3390. Peak HP 4880

041 cam
Peak TQ 4100. Peak HP. 5800

Changes with 1.65 rockers
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067 cam
Peak TQ 3280. Peak HP 4980
This is a rpm change of 300 rpm for peak TQ and 450 for peak HP.

068 cam
Peak TQ 3590. Peak HP. 5270
Change in peak TQ 330, change in peak HP 480

744 cam
Peak TQ 3730 peak HP 5370
Change in peak TQ 340 change in peak HP 490

041 cam
Peak TQ 4500. Peak HP 6380
Change in peak TQ 400, change in peak HP 580.

This is why for spirited street driving in high gear you want your rear gearing to have you right in the start of where peak TQ is coming in.which is usually 600 to 1000 rpm below the rpm of peak TQ.