new carb issue

[fdbdw]

71 c10 350 hei
Just installed a performer eps manifold and 1406 carb, previously had a 2bb roch. It seems to bogg down a little when I step on it, was wondering if the timming should be advanced more than prev carb and or go a little tighter on the lifters, I have the timming set at 10btc manual calls for 8 but living at high altitude 10-12 works better, valves set at 1/2 turn after zero lash, wodering if 3/4 and or 12-14 btc would be better for my new app, any thoughts or ideas, thanks