Cliff,
We just finished restoring a ’67 Firebird 400 and have had the carb rebuilt twice by a shop we’ve used before but may need your help. Never worked on a Quadrajet before. When it went back the second time, he changed the main body and that number is: 7029250 NF
Current Problems
Rough Erratic Idle, sometimes surging.
Wants to die at Stop Signs.
Vacuum Reading at Idle: 8 inches
No Found Vacuum Leaks
Idle Mixture Screws Have Little Effect.
“Once warm, if I close the choke butterfly, it smooths out and vacuum goes to 10 inches”
Engine:
Original Compression Ratio: 10 ¾ I believe.
Heads redone but no porting.
Stock Intake Manifold
Comp Cams Factory Muscle Cam #CL51-116-3
Lift: .516 Int and Ex
Duration: 292 Int 303 Ex
Duration @ 0.050 231 Int 240 Ex
Lobe Separation: 114
Lobe Centerline: 114
Comp Cams Lifters and Valve Springs
Dougs Headers
Magnaflow Mufflers with 2 ½ inch exhaust system
Distributor recurved, vacuum advance limited to 10 degrees, initial currently at 12 BTDC
Any advice??
Also: This car had the thin metal heat shield between the carb and the intake. When we took the car apart, the metal shield was between the carb and the base gasket. I've heard others say it goes on the manifold first, then gasket, then carb. Which is correct??
Thanks
