Better fuel economy Goodwrench 350

[Fairlane514]

I rebuilt my 1984 quadrajet with one of Cliffs kits. It is completely stock and I did not mess with APT. Its on a Goodwrench 350 with stock everything in a 1984 Cjevy C10 short bed 2wd. 700R4 transmission, and 3.08 gears with 255/60/15 tires.

Motor has stock intake, cam, I replaced the ESC HEI with a regular HEI with adjustable vacuum advance. Shorty headers and 2 1/2 dual exhaust with no cats.

12 degrees advanced timing at idle and 10-12 degrees more with vacuum advance connected to full manifold vacuum.

Motor runs fine with good vacuum around 17."   So far it gets about 8-9 MPG in the city.  Pretty sure the Goodwrench is low compression and is rated at 260hp.

Would jetting dow help? The jets were not stamped, but I assume 73.

The truck was originally equipped with a 305 and this carb came off of that motor.

Would a lower rear gear help, such as a 3.42? The truck is driven mostly in town.

[Shark Racer]

Jets will shift the entire fuel curve on the primary side leaner or richer; rods and rod adjustment will change the actual cruise AFR. Unless you're pulling lots of hills or on it a lot, jet changes won't have a major effect on fuel economy unless they're just WAY too big.

Are you running a M4M qjet along with your mechanical distributor? And how are you managing torque converter lockup in the 700R4? Lockup is worth some MPG.

The APT adjustment is probably the way to go.

[Fairlane514]

No hills here in Houston.  It does shift into overdrive around 45 mph.....the lock up is connected in the original configuration.