There's no reason the 305 should be any less effective, or reliable, than any other smallblock Chevy V-8, BUT, it takes a little more work to make one live up to its potential. The only difference in the 305 and the 350 is the bore size, which accounts for the cubic inch difference. They've both got the same stroke, and similar torque potential if the compression is correct. Flattop pistons and a little cylinder head work will turn the 305 on like any other smallblock engine.
That being said, you've still got a better truck engine in the 292, and the money you'll spend installing and modifying the 305 would be better spent freshening up the six. There's only 13 cubic inches' difference in engine size, so a rebore and some cylinder head work will get you the same size engine, with gobs more low-end torque if you stay with the six. With the right cam, valves, carburetion, and exhaust system, the 292 will run rings around the 305, too!
Jerry
