hey guys i own a 72 chevelle and it has been backfiring. I have been told it is probably the timing or the choke. Where is the choke in the carbuerator and also how can i adjust the timing? Thank you so much.

need to no which carb to comment on the choke. Lots of posts here on timing, do a search. Before doing either, make sure the ignition tune up is good -- plugs, cap, rotor, wires.

I agree with zeke67 on the basics of the tune up. Check all that before you bother with anything else. Fresh plugs, cap and rotor are easy to replace. Make sure none of the wires are burned through or cracked which will cause a misfire. Set your timing at 14* at 800 rpm or so to get you in the ballpark.

I doubt the choke is the problem. It's the flap on top of the carb if you want to make sure it's not stuck shut or something wierd.

Chevy V8's can have a misfire condition on acceleration if the accelerator pump is too lean. This is a problem when mis matched or old parts are used. If after insuring you have a good timing, total of 31 degrees all in by 2300 rpm, and good plugs wires, cap etc, try a little more accelerator pump. i have seen this happen too many times. Shade treee mechanics that swear it is an ignition problem and all that is needed is more accelerator pump shot. This has to do with 18436572 timing and 5 burning lean and 7 backfiring.
good luck

I agree with zeke67 on the basics of the tune up. ...... Set your timing at 14* at 800 rpm or so to get you in the ballpark.

If it is a stock engine with a stock cam I would start with 8 degrees at idle and then confirm the settings (all in) as shown below this post. I think 14 degrees at idle is a bunch for a stock motor, but total timing is the most important measure. Increase the RPM until the advance stops (all in). That should not be more than 32 to 34 depending on who you talk to.

Chuck