When I changed my '67 Newport from the original AFB and intake to a Torker 400 and the (allegedly) matched/calibrated TQ 9801 (allegedly calibrated for a '70 383 4bbl), it was not ntil I put the thick OEM-style base gasket under it that it ran better. I'd read (somewhere) that the throttle plates being too close to the bottom of the plenum caused fuel distribution issues, but spacing it up 1/4" made a definite difference over the (supplied) thinner cardboard base gasket. It ran good, but was not that much better than the stock parts, other than WOT power. Mpg increases didn't really happen, either.
I'd been using a sodium-based valve recession additive. After the car sat for a while, I was going to take it to a car show. It cranked and cranked and didn't start. NO accel pump shot. The additive had glued the accel pump circuit's "anti-pullover weight" closed. When I finally discovered that and free'd it up, everything as normal.
I later took it off and put a '70 Holley 4160 I'd bought at a swap meet. I kitted it and it worked good. That's what's on it now. I kept the TQ for later on. I like the design of it AND the triple-booster primary venture. For some reason, at least on that application, kind of lack-luster.
When I saw the then-new Street Demon, I did a double-take! Especially with the optional phenolic fuel bowl! A definite knock-off of the TQ, right down to the tube from the bottom of the accel pump to the pump shooter! So, when Summit put them on sale, I got one.
It appears the TQ is a "metering rod" carburetor, but on the bottom of the single power piston, there's a "nub" that rides against a flat "board" in the throttle body. The "board" is modulated by the primary throttle position. It ensures that a particular placement of the power piston happens at dedicated throttle opennings, kind of over-riding the power piston spring in the higher-vac situations. I know the later ones have it, but don't recall the earlier ones? But never was concerned, either.
The other thing about TQs is their height, compared to an AFB/AVS or Holley 4bbl.
I acquired a NOS TQ for a '76 400 LeanBurn application. I bought it at a major swap meet. The seller was a dealer who had raided his obsolete parts for some things that didn't make the trip to the dealership's new owner. They might have chunked it anyway. New in Box!
I also got a Carter StripKit for TQs, too, from "back when" in the middle 1970s.
ONE thing about poor fuel economy, the piston and ring wear issues come from the unburned fuel making it into the motor oil via blow-by. On an engine with good rings and such, the motor oil should not color from fuel contamination very soon. It should remain "clear" for a good bit, especially on a newer rebuild. IF you can smell hydrocarbons on the dipstick, the engine is running too rich or has a fuel leak into the crankcase.
Thanks for your input.
CBODY67
