didn't you just join up or I saw you on 67-72chevytrucks? same name? I'm benoit454 on there.
Anyways yea you can make a 305 fast, good rear end and trans. help alot. I got a monte carlo out front right now with a 305 that came in dad's 84 c10, nothing done to it but bypassed the esc dist. 4 bbl edelbrock instead of the quadrajet, and long tubes. it's got a th350 with stock TC, 3.42's out back and it'll smoke the tires off of it as long as you wanna smoke em for. When it was in his truck he had a stock trans, th350 stock tc, and 2.73 rear end, it wasn't too terrible, it actually moved it pretty good but no tire smoking. It ran better with that motor then it does now with a 350 that has 2.02 heads, comp 268h cam kit, double roller timing set, weiand action plus intake, mallory wires, long tubes, aot of bolt on stuff and the 305 ran better in it then the 350. This same 350 was a pure beast in another truck we had. But it was 3 speed stick shift and 4.11's I think. They can be built, but it costs more because ppl don't do it. Everyone throws em away for 350's. if the block and internals is strong I'd build it up some. If not and its got high miles, just find you a 350 and build it from scratch.
Not much to be done for power adders, in stock form that is, tb spacer, injector spacer, cold air kit or open element, headers, exhaust, chip, heads, intake, tb itself, ignition upgrades, etc.
First off you should do a good tune up to start with good name brand stuff like msd or accel whatever you like, cap, rotor, coil, wires, plugs. Then go from there.
Also find out your rear end ratio they make a big difference.
