Whats the difference between the crane 13757 rocker and the 13767 rocker? I couldn't find anything on their site but I have a box of the 67s.

The 13757 is a 1.6 ratio
The more standard 1.7 ratio is 13763.
Are you sure about the number? I didn't find a 13767 on summits site.

Yes I am sure of the numbers, I couldn't find the 13767 number on the Crane site either.

Mystery solved, the part # has changed to 13763

The 13767's are a new version by crane. They are pre notched to clear the stock valve covers. No need to grind the corners off anymore. I just put a set on my 502MPI. They worked great.

I have a used set if anybody needs them?

Nothing against you, but I never understood why people would grind on rockers and desturb the integrety of the rocker when a new valve cover for that depth is so cheap. High RPMs on the water , well can you say snap crackle pop...

Thats how they did it from the factory . it just on the back corner . it doesent hurt it .

I've never heard of anyone breaking a Crane (or any other brand) rocker arm and attributing the failure on grinding the corner for cover clearance. There must be several thousand motors right from Mercury running with this setup.

Crazyhorse I agree. If you think of it there are that same many thousand rockers out there w/ an extra 500lbs. over the nose still running today.That radius ground on the rocker causing a problem is like the chance of getting hit w/ a dick in a rainstorm .