Is that 262 advertised duration with 512 lift? Solid, hydraulic, roller, flat tappet? Do you have a grind number so we can see the specs? What is your compression ratio? Wieand intake... but dual or single plane? So far, it may just be a simple lean tip in. Is the pump set correctly too? I can't tell you much for intial timing yet, but I would think 12-14 would do much better. How do you have your curve set on the distributor? Using vacuum advance or mechanical?
There, answer these any we may have a little better picture of what you have.