the 305 vs the 350 is a big debate and if you are talking about a motor producing power on the stand, then the 350 will get more power for dollar yes, I agree the 350 is a better motor all around, more "plyable" for those who want to modify, but what are you modifying it for?  torque?  horsepower?  it all depends?  you can get better high RPM power, or lower torque power, but all in all dollar for dollar the 350 will beat the 305 to death, just cause there is more parts available - then determine what you are mating the motor too?  a 700r4 tranny with overdrive?  a 350 turbo?  a 200-4r?  this all makes a big difference when putting power to the pavement, a 305 in a light car with the 200-4r is goign to feel stronger cause power to weight ratio, but stick a 350 in that same car with a 350 turbo tranny and you have something will impress you more - in a truck a 305 will make you cry on the interstate if you try to pass with the 700 r4 behind it.  this is taking a stock gm goodwrench motor, decide what you have, what you are going to use it for, and longevity - if you stick headers on a motor you loose the easy way to do air conditioning, take it ALL into consideration when doing your ride, and dont forget your budget, is it all there now, or will this be an ongoing upgrade?  

I have a 305 HO in my 76 lwb pickup and I am very pleased with the power! It has a few bolt on's( headers,hi rise alu. intake & so on. The tranny is a 79 camaro 4 speed with 373 gears.
This thing will do alright for what it is!!  

No offense, my friend, but the 305 make a great ship anchor.  My parents, way back when, had a 79 Monte Carlo with a 305 and metric trans.  This thing was a gutless wonder, whose only good use was when I snuck it out at fifteen for the occasional joy ride.   After they blessed my uncle with the privilege of ownership, I ultimately hand the misfortune of rebuilding the thing; the rebuild yielded little to no, actual improvement.

This is a smog motor, plain and simple. Its  unworthiness as anything more is matched only by the transmission that Chevrolet placed behind it.  You’re lucky to get a sense of performance with the four speed, but that’s about it.  Don’t feel bad, however.  We all make mistakes. Might I suggest asking Santa for a stroked and poked, 383 for Christmas. Otherwise, a stage three nitrous system would add a lot of temporary fun and a deserving death to the king of the smog motors…