I just need to know what is the original style radiator cap that came on our cars. Mines an 89 iroc with a 350 tpi. I have found 3 different styles of the original ac delco part # of rc27 or gm # 10409635. The 3 that come up are a round silver cap, a round cap that has turning ears and a black label and a black plastic cap. For you guys with unmolested cars, let me know if you still have the original cap and which style it is. Thanks.

 

My cap is round metal and says AC RC27 on it (made in England). I believe it to be the original cap. My car is a 90 Iroc L98.

 

Thanks 71nova. I thought that would be the original type cap. I knew it wouldnt be the black plastic cap. Maybe on 4th gens but not on 3rd gens. I guess they changed the design of them over the years and kept the same part #. Thanks again.

 

I got a couple if you are looking for one ...