static only when engine is revved?

since you said you have no noise when using only one set of RCA cables, this can not be a problem with the grounding of the radio.  It appears as though you may have a ground loop problem.  The first thing you need to do is perform the test at the top of this page. 

http://bcae1.com/images/rca/temporaryrcashieldrepair.html

Test each set of jacks on the back of the radio.  The rca cables must be unplugged from the jacks while testing.  If you find that the problem jack is not grounded, you will need to do the temporary repair or get the deck repaired.    If all jacks are grounded, you need to call around in your area and see if you can find a shop that sell PAC products.  The item you are looking for is a PAC SNI-1.  It is a ground loop isolator.  You should be able to find a shop that will let you try it to see if it fixes your problem before you buy it.  We do it all the time.  It is a directional device, it is made to be mounted behind the radio.  Have your radio easily accesible when you get there.  If you can not easily get the radio out there, you can put it at the amp.  The only problem is at the amp it will cut your low frequency output in half.   But it will let you know if it will eliminate the noise.