Moreada, where about do you reside at? The answer is not too critical but it is helpful.
I see and I have a few questions about the ad you have presented.
The intake is cast iron – and is not fun for us old timers to install (or even remove) when bent over a fender.
The intake shown is not a ’74 model. It is a ‘78 to ’84 piece because of the smaller and angled bolt holed thermostat housing (black arrow, above). If will fit on any FMJ-body small block engine (which I will discuss more on that, later) without A/C or with the Aluminum C171 A/C compressor. It will not fit on cars using the cast iron RV2 A/C compressor.
About ½ of all Thermoquad carburetors are good ones (mostly the early ones). The other ½, the later ones (which includes all used on FMJ cars), are not as user friendly. What I would want to know before buying any Thermoquad is what the Model number is. It will be on the Left side rear corner on base plate and will look something like this:
Black arrow location
pictures swiped from eBay.
The top line will look something like 9123s (which is the
only important number on the carburetor – which
is the Model number). The bottom line will look like 123 4 (which is 123rd day of ‘74 (or ’84).
In the case of the above photo it says 9103s (second line) 179 7. Based with this information, the Model number is 9103s, which came off of a 1977 B or C-body 400 ci automatic car (non-High Performance). It is a 49-state calibration (not California). This one also has an Idle Enrichment attachment and has a High Altitude compensator. It also has large primary bores (which most big blocks came with, anyway).
The date code tells me carburetor was made on the 179th day of 1977. This particular carburetor (the one in MY photos) rates in the middle of choices (not the best but not the worse choice).
The carburetor in the ad – I do not know enough to recommend it, or not. Not without more information about.
When looking at a used carburetor, always make sure all shafts and linkages operate freely. In this case you have the primary shaft (attached to throttle stud), the secondary shaft (may have to finger a couple of linkages to get that shaft to fully operate), the choke shaft, the air valve shaft (big trap door on top back, and so forth. If anything is not free or will not operate – just walk away and don’t look back.
The choke mechanism shaft is missing from this picture (yellow circle on top photo) – so you will need to get a Thermoquad choke mechanism (white arrow, top photo) to get correct missing part (which is not a bad idea, anyway).
As far as intakes go, there are two different sizes. 318 2-bbl and 4-bbl (non-police) as well as 340/360/318 4-bbl police.
Either will bolt onto each other – but you will have a major port size mismatch.
When looking at small block cylinder heads or intakes, the way I can tell them apart is I take a hand with all fingers pointed straight ahead. I take my thumb and hold back the little finger (so only the middle three fingers are sticking forward). Then stick those three fingers into the cylinder head port or bottom side intake port.
If all three fingers fit upright into hole (or mostly fit) then you have a 340/360 (or 318 Police) head or intake.
If there is no possible way for all three fingers to fit – then it is a normal 318 port (unless you have really small hands).
Being that you already have a 2-bbl – you will want to stick with the small 318 port intake. A true 4-bbl 318 intakes are not easy to find. The intake I highly recommend, in this case, is the Edelbrock Performer (not the Performer RPM, which is different) part # 2176 (or # 3776 if you plan on using EGR). It looks almost like a factory intake, but is much lighter and works better.
My thoughts about this ad purchase. IF (a big if) I was going to use a cast iron intake and if carburetor was a good unit (working and had a good or decent Model number) – it might be worth $75 – but I would pass and here is why:
Personally, I would not install a cast iron intake onto any engine – when aluminum aftermarket (or Mopar Performance) intakes make more power, they lighten the car, and are mucho easier on the ole back to install (see above notes).
Also, Thermoquad is by far my favorite carburetor. I would get one of the good ones, though (eBay or other). Let me know if you find one and I can give you my opinion on it. If seller does not give you the numbers - from the location provided, above - then educate them or walk away.
Other items you will need, is air cleaner. Having a 4-bbl factory air cleaner is best if you live in a cold weather area because of the exhaust heated air. If you live down South (like Florida, Mexico, etc.) then any 4-bbl air cleaner will work.
Sense the carburetor is located further forward on intake, the throttle cable is longer. A 2-bbl throttle cable will almost barely fit – BUT I HIGHLY
DO NOT RECOMMEND USING ONE. One blip on the throttle, the engine will tilt to the passenger side and now your throttle is stuck OPEN. Not a good thing and it will CREATE a BAD DAY, real quick.
You can purchase a new throttle cable fairly inexpensively - and a lot cheaper than a car replacement and/or a hospital stay.
The next hard part is to locate EITHER a proper small block 4-bbl transmission kickdown linkage or (much easier) get an aftermarket kickdown cable system. IF you don’t do this – you will have transmission failure in a few short miles. IF you do the cable (or proper linkage), then everything will be great.
If any questions, ask away.
BudW
