I have a 1993 honda civic ex with a h22a engine swap. It has DC headers and valves are loud. Is this normal? It runs great. Also it pops sometimes when shifting from 2nd to 3rd gear is that normal? Thanks!

 

I wouldn't say that having a set of tubular style aftermarket headers like the DC ones you have should be cause for you to hear excessive valvetrain noise but it does technically happen.
Only because there is a possibility of different thicknesses of material but the change would be so very slight, probably a decibel at most that I doubt it is your problem.
H and F series engine are known to have loud noisy valvetrains. Maybe take a voice recorder or video of the noise?

I'd say you should check the following:

• Ignition Timing
• Valve Lash Adjustment
• Quality of Fuel
• Camshaft Timing

I say this because if your valve lash is off then your going to be hearing the excessive play as a whacking or tapping sound.
Check your ignition timing because if it is not your valve lash then you might be experiencing some pinging or detonation (the combustion event is occurring too soon in the engines cycle).
This can be caused by poor quality fuel or fuel with too low an octane rating as well as improper cam timing (If fitted with adjustable cam gears or if the timing belt has slipped a tooth) and improper ignition timing. An engine with slight detonation will cause a sound and it will sound like loud valves.