Well this happened last year. I have more exhuast and pressure coming out of my left bank than the right bank at the tips of the tailpipes.
My headers do not seal perfectly on the left bank but not enouph of a leak to make that much of a differance.

I have headers, 2.5 pipes and 2.25 tail pipes.
since then I have blown up both my mufflers so I can no longer tell whats going on pressure wise.

I had checked the rockers to see if they were set right and they checked out fine.(thinking the valves were not opening fully)

I was wondering if the pressure differance could be just becuase the headers are not cemetrical or bent the same since new.
Has anyone heard of this occuring ?
I noticed this the 1st day I had the engine runing in my garage while I was starring at it in the garage from the driveway.

Maybe you should try performing a cylinder leakdown test to see if there might be a problem such as worn/broken rings. Or try opening the oil filler hole with the engine running and see if there is any air blowing out. Check your spark plugs, wires, and distributor to make sure all cylinders are firing properly. If nothing else maybe you should try a crossover pipe in the exhaust.
graemlins/thumbsup.gif

I forgot, the headers being symmetrical or close to it, shoulden't affect pressure between left and right cylinder banks. It's the length of the header tubes that would probably make the most noticeable difference. If they aren't tuned length headers, the exhaust pulses on one cylinder bank may be combining in a different sequence than on the other, for example, you may have the exhaust from 2 cylinders going into the header at different times but because of different length tubes the 2 pulses are combining in the exhaust pipe and might make it seem like one side is giving more exhaust than the other, when it is only the exhaust pulses combining rather than coming out in an even, spread out sequence. This is where a crossover pipe comes in, it allows uneven pulses to crossover and cancel out each other in the exhaust.