Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

tunning 350 c-10 and choke?

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Metal Man:
Some extra info :
84 c-10 short bed
350 "hecho en mexico" low compression crate engine Heads: Cast Iron, 76cc
Valves: 1.940” / 1.500”



I am also looking at getting rid of the spacer if it will help with fuel economy and will need to purchase those parts and gaskets for that from you also.

Metal Man:
I adjusted the float level to 3/8" to see if it would make a difference but did not see any change.
I also disconnected the EGR and took it for a drive. Heres what I came up with while using the narrow band meter.
12.5 @ WOT
13. @70MPH slight load, uphill on highway
13.-13.5 @70MPH no load, but the meter is "fluttering" off and on also. I am thinking the metering rods are going into jets at high vacuum(leaning out at no load)

Meter goes lights out at cruise, 45 MPH, but at the slightest movement of throttle the lights come on( seems on the edge of lean)

This is reading the meter no complaints with engine operation through power band. Engine runs smooth, at idle, cruise, and WOT. Off idle acceleration is now smooth also. 

Cliff Ruggles:
Those engines have had open exhaust crossovers in the intakes for decades with no negatives anyplace.  Most like flooding in lieu of "boiling over".  That comes from using over the counter parts, which are low quality and never the right parts.  Compensating with a low float setting is not the answer, as fuel level in the bowl effects the fuel delivery to the engine (tune).

Blocking off the crossover(s) also create tuning issues, as the intake will eventually heat soak anyhow, but it just takes a LOT longer, and in really cold weather it will run very poorly, and even "ice" up.

Tuning should be done to achieve best results in all areas, instead of chasing a meter around.  I'd put a piece of tape over it, tune for best idle, off idle, light/heavy/full throttle, then take a gander at the meter to see where your "base" settings are at.  A little fine tuning either direction from there and watching the meter is OK.  These engines have a pretty broad range of A/F they will tolerate, want and need, as some as just a LOT more efficient than others.

Don't forget distributor tuning, it is equally as important as the carburetor, and will allow for leaner mixtures at light throttle cruise, etc.....Cliff

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