ok, not all these have to do with carburators. so i have noticed the admins have been touchy but they are tech well here goes.

first question is that i have noticed about 25-30hp difference from a 305 4bbl and a 305 HO.. what is the difference? and what is the differnece from the L64 and the LG4. i have the LG4 in my 84 trans am and i eliminated all the computer stff (pollution pumps?) and all the stuff you don't actually need, beings i don't need to pass any emission tests and i was thinking would this give any extra HP and if so what am i pushing now instead of the 150hp.

next question:

i bought a holley 4160 600cfm carb.. i believe it's 4160. i also purchased a holley dominator intake. now when i put everything on i had a problem with the choke fuse, it kept blowing. my father's carb also did this on his 305 in his truck but he forgot what he did to get it to stop. what should i try or look for?

next question:

i am not very good with carbs and i was watching horse power tv and they said holley comes with high jets and should be lowered if you're not pushing that much horse power. what kind of jets should i put in it and if you have a website with the jets could you link it to the page of them. or do you guys think the jets would be fine as long as i'm only loading up because the choke stays open?

next question:

i would like to put a cam in the engine. does anyone have an idea of a good cam to put in or specs i should use? or a place to match cams for the carb and intake i have? or anything would be helpful.

ok thats my questions they all have to do with carburators so admins please don't close my post i need some help here.

 

Well, it was mostly about carbs...

For the jetting, I would look in the owners manual, and see if you can tune it to your specs using the reference chart that the owners manual should contain (at least the edelbrock carbs do), and see if they have a jetting reference chart.

As far as the choke goes, Im lost as you are. I try to stick with the edelbrock stuff.

For the cam, look on holley's web page. They have a performance package that matches the cam to the carb and intake you have (The street avenger package, maybe?), much the same manner as edelbrock did in the performer package. Or, you can get hold of a crane catalogue or call them, and they will try and match one of theur cams to your specs.

 

In 1984, the differences between LG4 & L69 were:
Compression (LG4 lower)
Cam (LG4 milder)
Exhaust (LG4 smaller)
Air cleaner (LG4 a coffee stir stick in a milkshake world)
Knock sensor (LG4 didn't have it)
Electric radiator fan (LG4 didn't have it)
Carb tuning (LG4 secondary AV probably doesn't open as much, rods/hanger leaner)
PROM tuning (LG4 less aggressive ignition advance)

With the changes you made, you're probably pushing about 152 HP. Power to weight increase slightly more than that because of the mass you've removed.

 

my carb: http://holley.com/HiOctn/ProdLine/Pr.../0-80457S.html

my intake:
http://holley.com/HiOctn/ProdLine/Pr...SM/300-64.html

can't find what cam matches it yet thoug.

 

ok i might have found it... under features it says

Features
High rise/dual plane design
Idle-6000 RPM power band
EGR provision
Square flange carburetor mounting
Lunati camshaft kit is available under P/N 06109LK.

Carburetor Recommendations
For Street Legal carbs. 0-80457S (600 CFM); 0-4776S (600 CFM); 0-80508S (750 CFM).

i have the 600cfm carbrator so would i order that part number for my intake and carb (06109LK) i think it's a big cam.

specs of the cam:

1500-6000 (rpm)
272° 284° (Adv In/Exh)
216° 228° (@ .050" In/Exh)
.454" .480" (@ Valve In/Exh)
.303" .320" (@ Lobe In/Exh)
112° Sep 107° Int C/L (Lope Sep Int C/L)
01°BTC 35°ABC / 51°BBC -3°ATC (Opens/Closes @ .050)

so if thats the part number for the right cam i am looking at how does that sound? it says decent idle what does it mean by that.. sorry guys i'm only 17 i'm learning sorry for all the questions. but my dad bought a cam once and it was too much for the engine and i don't want that to happen to me

 

also one more quesiton:

how does the 86 trans am LG4 put out 165hp and the 84 LG4 only put out 150hp. whats the difference?

 

They changed the compression in 86, upped it to flat-top pistons like the L69, that's where the extra HP came from.

Like five7 said, what you've done so far hasn't even begun to nibble around the edges of what limits the LG4's performance. You haven't done anything of any significance at all to affect the engine's power output.

The way you improve a motor's performance isn't by unbolting big shiny things that sit on top of it, and bolting on romantic-sounding familiar performance name brand parts. It isn't by stripping all the "emissions junk" off of it. None of that sort of thing will get you anything but an expensive, unreliable, gas-guzzling pig, that's no faster than it was when you started. The emissions equipment on it costs almost zero power, and the factory carb and intake are entirely adequate up to a power level far above where you are now.

The correct way to make your car faster economically is by identifying the weakest feature of the car (note I said car, not motor, because sometimes the performance limit isn't under the hood at all) and attacking it, one part at a time. Each time you find the performance bottleneck and do away with it, a new bottleneck will appear.

In the case of the LG4, the very first thing you absolutely must do, is to get rid of every single piece of the exhaust, from the heads to the street; and replace it with some sort of chassis-specific headers and cat and cat-back exhaust for one f the se cars, but not for LG4. If any piece you buy will bolt to any piece that's already there, you will be preserving the bottleneck, and using your money as the bullets to shoot yourself with.

The next thing is the cam. The LG4 has the weeniest cam GM ever put in a small block chevy; worse than the 267, or the 170 HP smog 350s of the 70s, or even 307 2-barrels. A good replacement is the Comp XE 256. When you do that, put in a new timing chain, and the valve springs that go with it.

The heads are the next bottleneck. Some of the people here have achieved pretty impressive flow out of them though, by careful porting. You can dramatically improve them with some porting.

After you've done that, the next thing it needs is a gear. They tended to put shopping cart gears in the LG4 cars, since they weren't really performance cars at all, they just were dressed up to look like it. (The LG4 is the same motor that came in the Caprice for example). A set of 3.42 or 3.73 gears will make it seem like a whole other car.

It needs an air cleaner. Again, resist the temptation to slap a big shiny chrome open element one on there, it may not even go faster than it does with what's there now. The one to get is (surprise) the L69 dual-snorkel one.

Notice I haven't told you to replace a single thing that you can just see with the hood open (except headers and air cleaner, and I even recommended a factory air cleaner.). All of the stuff that's really causing it to be slow, is invisible. I have not, and will not, recommend replacing the carb, or intake, or adding an aftermarket ignition, until after all the actual deficiencies of the motor have been cured. Otherwise, you're throwing your money away on those things. In your case, if you slapped that carb on there and retained the original distributor, and disconnected things that you don't know what they are and what they do, I'd bet money that I (or your) can make you car faster than it is right now by putting it back together the way it came.

The engine's ability to do work comes from burning gasoline. Each molecule of fuel contains a certain amount of energy; burning it releases it. Obviously you want to burn the fuel as efficiently as possible, which mostly requires that the fuel and air be fed into the engine in the correct proportion. Horsepower is work per unit time. Since work is a direct function of the number of gasoline molecules it burns, and each gasoline molecule requires air to burn, then horsepower is a direct function of flow (cubic feet of air per minute). You get more power by enabling more flow, not by making more parts shiny.

 

One little nit to what RB says above: The LG4 got 9.5:1 compression via flattop pistons in 1985.

 

well thanks for the info and like i said if i could go back i woulnd't have done any motor work to the car and i would have kept it all stock. where can i find that cam because i looked at a few websites and it's not on there. since i alreay have the engine dressed up and all messed up i might as well get headers and hooker cat back exhaust and the cam, if i can find it. so like i said could i have a link or something to the cam i should use. i might be getting an 86 trans am and if i get this i am just keeping it stock and forgetting about the motor and just make it look nice cause my frind has the 86 and that would be fast enough for me for now. thanks