69 chevy feeling tired!

[Longbedstepper]

Hi, this is my first post on this forum.
About 6 months ago I picked up a clean 69' long bed step side 4x4 chevy half ton. The truck has a 350 and a sm465 with 44,000 miles. It was 100% stock other than a 4" rough county lift and a set of 33s with chrome wheels. Motor was completely stock. When I first got it it ran good, but I could tell it needed tuned up. I took the old nasty quadrajet off and replaced it with a 1406 edelbrock. That made a noticable difference. Then last weekend I replaced the old points distributer with an msd hei with new wires and plugs and a edelbrock performer intake. My problem is when you step on the gas, all that happens is it gets louder. Doesn't pull any harder, may even lose power? I made sure the timing was right (10*). A lot of people telling me with the tires and 4 speed that's all the power I'm going to get but the thing feels very weak. I could really appreciate some advice!