engine cutting out down track after in 3rd gear!

Sounds like you got a Vac Leak as Well. You should be setting the idle at the highest vac reading..... 3500 Converter has nothing to do with it. You definitely need to fine tune your Carb, besides that You are either running out of fuel or your ignition is not up to the task as well.

Mine stalls to 4800....big deal.... Idle is at 1100 in Park and around 900 in gear. My cam is close to same as yours but Solid Roller. Lift is .634 at the valve.