Carter 9203 Thermoquad

-

Mojoe9955

Well-Known Member
Joined
May 14, 2021
Messages
948
Reaction score
672
Location
NJ
I saw a Thermoquad on FB Marketplace...free.
Its a nice looking carb, very clean, looks new or rebuilt. It's a Carter 9203 and when I look it up most of the info points to IH trucks and industrial/marine use, but also some mention later Chrysler small blocks. It might be rated at 750/800 cfm?
My question is will this work on a stock 318 with say a 256 cam and DP intake? Any other info/input would be appreciated as well
Thanks
 
Every carburetor will “work” with almost any engine as long as it is similar fuel type. With that said you will need to adjust and possibly jet / metering rod swap out to dial it into your engine. Unless you buy a specific carb built for your engine- you will need to do some tweaking to make it run the way you want. TQ are great because adjusting the rear door will get you 75% there. They are a very adaptable carburetor. Miss understood by the magazine builders crowd due to the “it’s hard” mentality. They are so adaptable- I’ve found them on many farm implements I’ve worked on over the years. They are amazing carbs if you just sit down and really think about what is going on and what you want.
 
That 9203 is a small primary unit. (Call it what CFM you like.)
This will work very well with the small cubic inch engine. It should have 3 vacuum ports on the front, looking at the front of the carb, the bottom right for the distributor vacuum advance, middle for the PVC valve, the left I am unsure of. On the rear, there is 2 vacuum ports, 1 for the secondary pull off, the middle for what ever you want. IF there is a hose connection on the top passenger side, that is for the vapor canister. Leave open if no canister is used.

Being a truck carb, the jetting should be on the rich side. This may play into your favor with headers and a small but larger cam helping to lean out the mix.

Rods and jets are available at the Carb Shop on line. No kits like for the AFB/AVS Edelbrock sells. Rebuild kits are available. Use the factory thick carb gasket, not the paper thin one when you mount the carb on the intake.

If your intake manifold you’re using doesn’t have a choke well, digging up something to manually pull the choke on and off can be a PIA. If you have the choke well, like the factory does or the Edelbrock Performer has, new chokes are available. Make sure you also get the choke rods retaining clip.
 
That came off a 1980 International truck. It's an 800 CFM with the smaller 1 3/8 primaries. Excluding the 1969 and 1970 Competition race carburetors, Thermoquads were only available in 800 and 850 CFM ratings, despite what some people believe. It appears the 9203 is a pre-emissions carburetor and probably a pretty decent one.
 
Last edited:

-
Back
Top Bottom