Im just wondering what would be the pros/cons? like performance and MPG-wise? Any insight would be greatly appreciated!

 

There's no use for this. Some will say doing it is the greatest, some will say it makes you car get 5 mpg and lose 20 HP (it doesnt, but ya know what i mean)

 

I`ve heard talk about its easier to get more HP outta a carb.

 

stock TBI flows 450ish CFM

smallest carb you would stick on a 305 would be a 600cfm.

currently the entire engine is a bottleneck for air... the air cleaner intake sucks, the tbi sucks, the intake sucks, the heads sucks, the cam is tiny, the exaust ports suck, the exhaust sucks.


going to a carb would remove one major bottleneck however, you wont see much of a increase until you remove the other bottlenecks.


so by "better" if you mean cheaper to make some power, and to change with mods, YES.

however, you are getting a carbed car still and you lose the benifts of EFI..... even though most of the benifts are lost due to the TBI instead of MPEFI but hey... whatever...

 

how would the mpg be?

 

the mpg really depend on your setup. If you get a non cc rochester q-jet carb (~750 cfm) with its small primaries, you probably wont loose much in the fuel economy dept. Bear in mind that the stock tbi is rated at 3 inHg where as the carb is rated at 1.5 inHg so theyre not on equal footing.

 

it all depends on how far you are willing to go, trying to build a 350+ HP 305 Demon then i would say go carb, but if you are just trying to get some performance out of the 305, stick with the TBI, the TBI is not the problem with the L03, it can and easily supports the L03, it is, like previously stated, the air intake, intake, heads, cam, and exhaust, that is the problem. The stock TBI unit with some turning has the potential to support around 300 HP and you could always upgrade to a 454 or Holley 2" TBI if needed. So let us know what you are planning to do to your car, is it a daily driver, does it every see the track, emissions testing?, etc. and also do some searching, there is so much info on this website its not even funny.

 

Its a daily driver, no emissions (im in florida), yes is sees the track sometimes.

 

if i were you i would stay with TBI until it was necessary to convert to carb.

 

no its not necessary, i just want some more HP

 

definately not going to get any more HP by just added a carb to an engine that wont benefit from it, heres what you should do first

These should be your first mods, in my opinion
Headers, hi flow cat, 3" cat back
open element, adjustable fuel pressure regulator, Ultimate TBI mods (look at tech articles)
3.73 gears and posi
and maybe some misc. mods like chips, pulleys, spacers, ignition boxes, etc.

That would give you a nice power increase and make your car a whole lot faster.

 

ya what he said...sept 4 the chip, wait till u swap out heads/intake/cam then ull need a custom burnt chip, dont waste money on an off the shelf one like i did

 

yeah, i definately wouldnt spend money on those expensive chips, i just got one for 30 bucks from www.tbichips.com, seems to work pretty good and is probably the cheapest performance chip you can find for a TBI.

 

for any reasonable HP without spending ALOT and having a "extreme" 305 you basicly need a new engine. (keep in mind this is my opinion and hear me out)


first of all, like i stated before, pretty much everything in the path of airflow needs to be replaced.. this also includes the 305s bore... the bore is so tiny that it shrouds the valves...


you can take a cheap vortec +cam setup and put it on a 305 and it makes mid 200hp.... the exact same setup bolted on a 305 is easily over 300. and its not the displacement advantage thats doing it as much as it is the bore/stroke

to get the same powerlevel on the 305, you're looking at a wilder cam, more compression.... basicly a hotter motor being pushed more... for no reason.

IMO for any more then roughly 200hp ( and a 200hp camaro is a joke IMO) you need to swap shortblocks.


you have 2 choices...

start saving up..
or
start mods, but only ones that can be transfered over later.... for example, headers/exhaust, heads even a nice roller cam would be great because they can just pop on the other motor later.


anyhoo thats my opinion.. and now my discripton of how a lowly L03 works:

the air is sucked in thru a thin snorkle where the restrictive neck is even more restrictive by a small butterfly valve... the air must then flow up thru the thin aircleaner where after passing thru it, it must make a sharp 90* turn down the throttlebody... the throttle body, even with out this aircleaner restriction, only flows 450 somthing CFM.... the air/fuel mixture then goes thru the flattest cast iron manifold that ive ever seen.. this manifold is so low that the air must make a sharp turn just to get to the port on the head. once there, it must pass thru the ****ty intake ports and around the tiny valves..... but the valves are halfway shrouded anyway by the small bore of the 305.... the 305 then uses its TINY amount of compression to try to extract some power from the raw fuel dripping in it, but alas, the stock timing is set at 0*, no where near where it needs to be to make any power. the exhaust now must flow out the ports, still shrouded by the bore and restricted not only by the valves and ****ty exhaust port, but by the small cast iron exhaust maniflolds... after passing thry the manifolds, it has to flow thru this TINY y pipe where it comes together in to a pipe that is still far too small for even the measly 305... it then pours into a cat... and after all these years of running like ****, of course the cat is partially clogged.... from there it goes thru the rest of the exhaust.