A 4 barrel carburetor that has a code of 9078S printed on it. A couple of questions about this carb.
1)is it possible to convert from a lean burn carb to non lean burn?
Yes. Though the I’d rather use an older unit to start with or at least one that has non emission calibrations. I’d need a picture to know exactly what carb it is for the mods. I don’t know every trick in the book, but, the first thing a lean burn carb lacks and a a distributor spark advance port on the lower left (drivers) side. This is simply not drilled from the factory. You can add this yourself & put a vacuum fitting in there for the distributor. After that, I need a visual.
2)if it can be converted, would it be worth doing to save some money and would this carb once set up properly work fine for my mild 440? By mild I mean 325hp/375torque.
Yes. The mods are easy. However, I never really liked the newer TQ’s modded that much. I haven’t a ton of time with them, but they’ll work well enough. The devil in the TQ is in the tiny details. At that power level, a 600 cfm AFB or Holley would work well. (Food for thought.)
These are known as the “850 cfm” TQ’s but actual cfm was closer to 780/800 cfm area.
I would check with a carb parts supply house to see if metering rods and jets will convert it.
You do not need rods and jets to convert a lean burn. Just to tune it. Jets are available on custom orders through I believe “The Carb Shop.” They have a single rod available last I looked. A 1966 rod.
To this end, I have used typical stock and Edelbrock AFB rods bent and clipped 3/4 of an inch shorter to fit the TQ.
Do not use the older 3 step AFB or AVS rods unless you eye ball them closely for modifications. The Edelbrock and OE 2 step rods are much thicker up top over the TQ rods and require drilling the TQ rod hanger or making your own which isn’t really that hard at all. Just time consuming with probably several tries on your behalf until you get it just so.
This will open up doors for tuning possibilities. With the large number of OE and aftermarket rods available, you may only need a couple of sets of jet to cover most any tune possible. A 02 gauge/sensor for tuning purposes will help in a huge way and help narrow down the amount of jets to order instead of guessing what you may need.
I’m not sure if anybody makes secondary jets. There long brass tubes. Not normal short jets. If you can find any, they are easily drilled out for a larger size.
See how the TQ works as is before anything else is done or attempted.
According to the Vannth guide;
Carb model number, year, engine size, trans, “F” federal, “IE” Idle enrichment
9078 77 440 AT F IE
Primary jet, secondary jet, rod sizes;
4098 - 5137 - 2159
(.098 -.137- .070 .062 .040)
Primary/seconds bore sizes;
1-1/2 2
Depending on what needs converted you’ll probably have $100 in that and a rebuild kit.
800 CFM is where the carb spec is. Plenty for the HP, big benefit of spreadbore carbs.
I use a vendor called Quadra jet parts.com for parts. They are always helpful when I call.
I don’t know what rebuild kits go for these days. But it is the solvent and small cleaning parts that add up fast. That Quadra Jet Parts.com is a pretty good place.
