"Thought" i had i timing set. When i bumped throttle to 3k rpms the light started bouncing all over. Brand new motor and ran like a swiss watch on the builders stand with and hei dist. Im running msd with a msd box. Did some reading and sounds like it could be due to the msd box and my timing light with the advance dial. Anyone else heard of this?

yes,a lot of advance style timing lites will give a incorrect reading.i have a 400 dollar snap on that goes crazy with any msd box.

Trade him even up and be happy.

Crazy huh ? And a 25+ year old cheaper Craftsman advance dial light doesn't.

Ebay new around 75.00

i had one of those,it took a crap years ago.

Well chit. If set the dial to 0 and go off 34 degree mark on the balancer and the tab would that work? Planning on going to the water tomorrow. Ill try to find another light.

Also, Make sure your leads from distributor, are wired properly. Purple, does not go to purple. I wanna say on those, its purple(dist side) goes to green, and purple goes to orange(dist side)

that will work.

This is most likely your issue. I had the exact same deal happen. Ran fine, but timing light issue.