shorty headers on a 305tbi in my 92, how big of a diffrence will it give me? where and what are the cheapesT?

 

The gains are substantial but you don't want to go with the cheapest. If you are buying a new set you want to spend no less than $350. The $200 kits won't cut it and will end up making you spend more money later on. Although not necessary, TBI cars benigit greatly from chip work after header installs. Some cars see volumetric efficiency gains of up to 10%.