well you can get a crate engine 350 from summit with like 250 hp and 300 tq sumthing like that for about 1600 with out manifold headers and carb but that wouldnt be a funn build up

350 are way easyer to make hp and tq
305s well there funn but a pain in the but i got one in mine and its quick and makes about 250 hp and no clue on tq but i always got the thought why didnt i buy the 350

 

yea go with something better than the 305 i have the same dylema as far as an upgrade. and i got some very good feed back. i have a 305 in my maro with about 265,000 on it and still runs good but and i love the feeling of my head pulling back as i floor the pedal to the metal. but if you can get the 350 go for the 350 or maybe something stronger than the 350