Edelbrock RpM head question

I attempted to use the stage 8 bolts on the 340 with headers. Ended up throwing them all in the trash can and went back to normal bolts.

The locking mechanism tabs would not go on because there was no room for them.
Might have been the size of the header tubes but the headers are w5 TTI.

Strange, I've have a few that I couldn't use due to header tube interference, but most are ok on mine. I like their stuff though, quality.