[Jack21]

Motor has 2500 street miles on it now. 351W, TFS 2.02/1.60 heads, Comp hyd roller 224/224, Ede Performer RPM, Holley 700 DP (4778), MSD distributor, Accel 300+ CD box & coil. Autolite 3924 plugs gapped at .045. FMS plug wires. Initial lead 14deg. Cent 20 deg @ 2500RPM. Vacuum 8 deg at part throttle cruise. Idle vacuum 16" @ 800 RPM.

Running too rich. Ignition or carburetion?

Took it to emissions test sta. If it's close to State emissions spec, then the motor is dialed in (for street use anyway). It isn't! CO around 3 % (ehh), HC 3000 - 4000 (way too high). Emissions tech suspects ignition problem, thinks motor is misfiring.

Carb. Not my first Holley. Some of you hate Holleys, and some of you love 'em. One of the advantages of a Holley is it can be tuned. One of the disadvantages is, it must be tuned. But once dialed in, it should need nothing except occasional cleaning. At least that's been my experience.

New carb. Box primaries were #69's. Now down to #64's. PV is 65. Engine seemed like PV open at cruise and some acc pump fuel getting into motor thru vacuum chamber. How? Throttle body - metering block surface is dead flat (these warp sometimes and have to be filed or milled flat), and not a cold casting (no casting porosity). Gasket embossed pattern gives no indication of improper sealing. Drilled & installed brass tube & O-ring in acc pump xfer channel to seal (not that it needed it from the gasket pattern, but to eliminate the variable). Replace PV again.

If it doesn't sort out, anybody using BG Speed Demon 650? Complaints? Praises? Anybody using Holley Pro-Jection? Complaints? Praises?

Ignition. Verified TDC actual vs pointer. It's off 3 deg. Checked dist rotor phasing and it's centered on #1 when plug fires. All plugs appear to be firing but dark & sooty. Checked coil output. Plug fires with a "Bzzzzt" rather than the healthy "Snap" I'm used to. This is the Accel setup. Checked with spare Crane HI6 & PS91 coil. Same bzzzt. Doesn't seem like a healthy enough spark to me???

Default ignition around here seems to be MSD6A. Does it snap or bzzt at plug? Should I scrap the Accel and get the MSD?

Thanks.