I am looking on RockAuto for distributor cap and rotor. There are two different types of AC Delco caps and rotors. Does anybody know what the difference is? I can't figure it out! I have a 1995 2 Door 4x4 Blazer with the W-code engine. Hypothetically, they both fit, but they have different descriptions.

 

I just ordered a cap and rotor from advance auto accel gm vortec with brass contacts, autolite professional grade wire set and ac delco iridium plugs. Advance auto parts has a coupon code if so i saved 35 bucks and got free shipping. I was going to order the ac delco cap and rotor but they did not have copper or brass contacts so I went with accel brand.