keep replacing cap and rotors

I have a 98 chevy 350 motor I replaced the intake gasket and the distribtor it was bad also. now after i did this i get about 4000 miles and have to replace the cap and rotor. the first time this happened the cap was cover with water and rust so i thought crack cap this sucks but i replaced both of them and forgot it. well now about another 4000 miles or so i burned up the rotor but this time the caps contacts were cover like the battery terminals with all the white corision. and no water was present this time around but both time the rotor burnt thru just before the point of contact to make the spark what can be causing this. the distribtor is a new one by the way

i have a '97/350 and when i bought it, the previous owner said he had problems with the cap rotor and said it was because of using cheap parts. he was getting parts at autozone because they were cheap. but he said to avoid the problem is to buy better quality parts. i havent had any problems since ive owned it.

just what ive heard,unsure if its really the problem.

well saying that is true i always buy my part from autozone but i have not had this problem before i changed the distribtor and both of those parts were replaced

Are you sure that your engine is properly grounded to not only the battery, but to the frame as well? Are all your wiring harness grounds intact and solid?

Buy a quality cap and rotor (brass contacts on the cap is usually a tip-off that it's a premium product).

Be sure to check your plug wires where they plug onto the cap. They may have corrosion from the old cap which is then promptly transferred to the new one! You can try cleaning inside the boots with Q-tips soaked in WD-40 but the only sure cure is changing the wires.

Do you clean your engine regularly? Do you rinse it off with water? Sometimes it gets into the darndest places, causing all kinds of corrosion problems.

There are sprays that protect electrical contacts from water, i forget what it is called, also if it is water getting in, try using RTV around the base of the cap to make a seal.