Which to use? i have a holley and thermaquad( for some season, don't care for Holley's or thermaquads), a couple afb's, and a avs. Like the avs, read how to put afb metering rods in them. Going on my 68 383 D100 pickup.

If you're comfortable with the AVS,then use it. TQ is a very good carb.

I would go with an AFB. All (OE) AVS's are lean due to the discombobulated gov't emission standards that Ma & everyone else was striving to keep up with. As you noted you can swap in eddy performer 2 step rods and short pri jets. put some JB weld in the domed metering rod caps then cover em with some scotch tape then turn them upside down so the mud will settle flat on the tape & let it set up for 2 days then remove the tape. likely there were more emission driven mods in the AVS's than just the metering rod/jet sizes. So if you have an AFB that you can rebuild that has tight bushings that would be my route. trim the cluster gaskets for an exact fit compared to the OE ones, rebuild kit gasket fit/quality can be poor & I like to lube the bowl screws with oil if they will be removed often as they go into aluminum.

So you don't like the most popular carburetor and you don't like the best carburetor.

Actually you have another option that combines both carb types you don't like, and that's the Holley Street Demon. It's like a modernized version of the T-quad, but being currently manufactured. That's what I'm going to spend my next carb dollars on.

The AFB is an easy choice, I like the AVS because it has the air door that's more accessible than the counterweighted ones that were on most AFBs. If you like this type of carb best, then the Edelbrock Thunder Series is what I'd pick for you. It's Edelbrock's version of the AVS and you can buy parts for it, new.

R.

What is it you think you can't buy for the AVS?

https://carburetion.walkerproducts.com/carter/carter-carburetor-kit-4bbl-afb-avs/

Only problem with the street demon is it is a pain in the booty to get hooked up. Just went through it, and haven't really dialed it in yet to know if it was worth the trouble.

May be easier if you are already planning on aftermarket throttle cable/kickdown.

Hooking it up to my existing 4 barrel bracket and one piece kickdown rod took some creative bending, 2 factory throttle studs, a holley lever adapter, lots of cursing, some lucky drilling, and a several spacing washers.

Love the idea behind it, and the fact that it could pass for a t-quad from 30 feet away, so I hope it turns out to run as good as they say.

Thanks. i am on a budget, and have used carbs to work with. Would like a thunder series carb.

Squarebore intake? Go for the carbs that match and the simplest hookup to fuel and throttle. AVS and AFB most likely also can be setup with the stock type choke.

There are some other criteria that are likely to be more important than which carb platform someone might prefer.

For instance; which carb will fit your intake (spread bore vs square bore), which carb is in the best condition since they all seem to be rather ancient (throttle shaft bushings come to mind), which one has the closest calibration for you current combo, which has the best selection of parts available (Thermoquad tuning parts can be hard to come by), the installer's familiarity with tuning each one, etc.

If the budget would allow, the new Street Demon would be my first choice, too. But I have not had the installation issues that an earlier poster noted.

I'd bet those metering rods are 2 step AFB rods. If they are 3 step AVS rods I'm on it.

It was running with the avs, with issues. i think it has the 3 step rods. Which is better, 2 or 3 step? Read i can't get 3 step replacement rods anymore. Carb guy told me he might have some.

Not sure anyone is making three step metering rods any more.

Take a look at this Carter jet and rod chart. I tried to post the charts themselves but couldn't.

http://jimsprojectgarage.weebly.com/uploads/3/0/5/7/30573187/1416930429.png

And an example tuning chart.

http://www.volvord.com/1406cal.jpg

Now that is typical of the charts for the 2 step rods. Just imagine what the tuning chart would look like for the 3 step rods. It would be about useless for most of us mere mortals. Besides, the number of pieces required to tune, which can be hard to find.

I like the CarterBrocks, but there is a reason that no aftermarket carb builder uses them. Virtually all use the Holley platform.