Hello,
I have a 1970 camaro and I built a 400 small block with a 600cfm carter 4bbl carb, weiand accel intake,174 xtreme comp cam and electric fuel pump. Here is the problem, my car has a rough idle and i like that but when i start to drive the choppyness of the idle continues though my acceleration. I also have a strong odor coming from the exhaust that my neibors can even smell. I have tried adjusting the carb and set the timing to 10 degrees below. basically i think it is misfiring so bad that the extra fuel in the cylinder is not being burnt and that why i get the smell and choppyness while driving. Where should I start to look for the problem? & or how?:confused:

First, I'd check the condtion of all plugs, determine if spark was reaching them, examine plug wires for burned spots, and make sure the wires were attached at both ends securely.

It sounds as if your engine is nether this or that...
A high rmp engine trying to run on the street by smaller carbs and stuff.
A hi rpm cam is designed to work right up there, anything too far below and...we the engine is not designed to, but does run.
The 1st engine we all built, we did this..well most of us (assumption)
Your cam rpm range, your usage rpm range, carb and most prob the dizzy curve do not match.
When they do match, there is more power THEN, and still a very respectable amount either side.

One hast to decide what is right for them, and match the componets to that
Be it a racer on the street, or a very quick street machine.

you may improve things lower down by getting an adjustable timing chain, the advancing the cam 2 degs to drop the power range.
Check dizzy timing and curves.
Butterflys havnt been drilled and carb scewed around with.

verify firing order is right on plug wires and/or

make sure you don't have a 4-7 swap cam, and plug wires setup for 18436572.
on a comp if it is 4-7 swap the last 2 #'s of the pn is 4-7.
I think it would sound pretty bad if this was the case, but it is a ground zero kind of thing to look at.

What is your idle speed? What heads(cc) do you have? That 274 isn't a wild cam and a 400 w/ flattop pistons you just about couldn't put too big of heads on it to hurt the dynamic compression ratio I'm thinkin.

I would have more advance, but we need a little info back from you.

Have you tried a different carb? I like Carters but 600 is a little little for a healthy 400

While removing the spark plug wires to re-run them I found 2 of the wires were burnt through:noway: from the header....... After replacing those the missing stopped and my power was restored. But I still have that really strong exhaust smell, if I am standing outside the car while it runs my eyes will start to water from the fumes. When I adjust the carb the vacuum only varies 1-2 psi ( I have a carter 600 cfm) I will be replacing the entire exhaust system with a summit kit but the smell will still remain. Any ideas on what I can do to stop the strong fumes? Also when I shut the car off it still hickups for 15 seconds or so.

Hiccuping? you mean dieseling or run-on after the key is turned off? Yes? someting going on with the timing or a HUGE vaccum leak.

FUMES? On the front of you carb towards the bottom, there are 2 identical flat-head screws about the size of a #2 pencil. Screw them to the right(clockwise) until the tighten. start the car. does it run?

it diesels after the key is shut off for a little bit. I did notice that one of the plugs on the front of the carb was cracked and falling apart, would that vacuum leak cause the dieseling? When i had adjusted the carb today if i did tighten the screws down you could tell a big difference like it would want to run.

sounds like a leak somewhere...car still idle with (Air/Fuel) screws all the way in and finger tight? thats not good. I am trying to find out if the problem is your idle circuit or not....
plug is cracked? a piece of the carb is broken?

sounds like a leak somewhere...car still idle with (Air/Fuel) screws all the way in and finger tight? thats not good. I am trying to find out if the problem is your idle circuit or not....
plug is cracked? a piece of the carb is broken?

A vacuum cap(plug) maybe Harley?

A vacuum cap(plug) maybe Harley?

how many are there? its a carter. ? I think the timing is off and the idle circuit needs to be played with....Just my .02:D

What would you set the timing at? I have it at 10 below right now. The carb is a carter and has one plug right now due to the other port is taken from the advance. How do you adjust the carb on these? Thank you for the help so far