A friend bought these valve covers on Ebay a while back, and is unfortunately having difficulty finding which vendor they came from. The long and short of the story is his stock rocker arms, with an original Chevy cam (4bbl truck motor, 1972), hung up on one of them enough that they stayed open. Just barely, and just on one side. A heads up for those of us who like this style cover. A few minutes spent clearancing them will work fine. Pic now attached.
I made these 1/2 in thick spacers to clear roller rockers and also adapt these old staggered bolt hole covers to fit a newer motor.
I had stock Corvette valve covers hit on my rockers once when I had them on upside down. I didn't had no idea they were non symmetrical but they most definitely were.
The Jalopy Journal
