Engine Detail

• 360 LA
• J-heads
• upgraded cam [recent], upgraded springs, stock rockers
• Edelbrock Performer rpm intake
• Rebuilt Edelbrock Thunder AVS 650cfm
• Carter electronic fuel pump [new]
• Factory electronic ignition
• Parts house plug wires
• Stock replacement plugs [new]

Issue

• Engine runs great below 3,500rpm
• Idles great, good torque, smooth running
• Starts to "break-up" higher than 3,500 that and really hits a wall at 4,000rpm
• It just won't rev higher than 4,000rpm
• It will not rev higher in neutral [no load]
• It will not rev higher in first gear [under load]
• Wideband steadily gets leaner and will hold at 16:1 [LEAN]
  • Lack of fuel, or lack of spark
• No popping, it just surges slightly and will not gain rpm

Fix Attempts

• Swapped ignition ECU, no improvement
• Reset ignition pickup gap to 0.008"
  • Perhaps a slight improvement.
  • Distributor is of unknown age [factory style]
• Adjusted AVS air door to "very loose" to ensure it was opening and providing air over the secondary venturis
  • no improvement
• Took carb apart, verified secondary venturi ports and jets were clear
• Checked fuel pressure with mechanical, non-liquid filled gauge on the windshield.
  • Solid 5-6psi
• Coil is a parts house brand and is only a couple thousand miles old
  • But that doesn't mean it isn't failing me

What I have not tried

• New distributor
• New coil
• Adjust float height away from factory specs
  • [doubt that's the issue]
• Driving it off of a cliff, North Texas is very flat
• Verified actual valve lift - flattened cam?
  • The truck drives great other than this condition

Edit - This is from yesterday, it's not "as jumpy" since I tightened the reluctor gap slightly, however the issue still remains.



Any ideas?