Edelbrock Performer Setup for Crane Purple 272 Smoothness

[1966Coronet440]

After the 318 LA in my 66 Coronet 440 being rebuilt about 15 years ago with a Crane 272 purple cam, an Edelbrock performer intake manifold and an Edlebrock performer carb she was noticeably more powerful, but never started easily or cruised 35-45 as smoothly. She had noticeable surging that killed the cruising enjoyment and acted like she had a dry bowl on start. She required juuuust the right application of gas during crank (which she never did before the rebuild)... After ages of chasing down the answer I recently got it figured out with the assistance of ChatGPT. I asked it to cruise forums like this one to find me other examples of people with my motor/cam/carb/top end combo having my issue and it nailed it on the first try. It suggested:

The Edelbrock Calibration kit 1487: https://www.summitracing.com/parts/EDL-1487
✔ Primary Jet: .098
✔ Metering Rod: 0.073 x 0.047
✔ Step-Up Spring: Yellow (4 inHg)

In order to produce:

• +4% cruise fuel (fixes the 40-mph surge)
• 0% power fuel change (keeps WOT correct)
• Enrichment begins earlier due to yellow springs
• Smooth low-RPM drive with the 727 + likely tall gears

While I'm sure I could've gleaned this from reading enough forum posts on my own, employing some new tech saved me a lot of the trouble and let me get down to business! She starts easily now and cruises like a dream again! Hoping this might help someone else!!

 

[1966Coronet440]

Forgot to add timing:

• Reset timing to:
  
  • 16° initial
  • 34° total
  • Vacuum advance to manifold vacuum
• Set idle mixture to peak vacuum (12–15 inHg expected).

 

[Geoff 2]

What is the timing at idle with vac adv connected to manifold vacuum? [ A good move, by the way ].

 

[lewtot184]

You don't state what model carb you have. I'll have to assume a 1406. If so go to a .101 jet and a 71x47 rod. All those automatic choke carbs are fairly lean. Also the vacuum advance may be pulling a little quick. That can be tightened up.

 

[1966Coronet440]

You don't state what model carb you have. I'll have to assume a 1406. If so go to a .101 jet and a 71x47 rod. All those automatic choke carbs are fairly lean. Also the vacuum advance may be pulling a little quick. That can be tightened up.

Yup- The 1406 I believe with the electric choke. Seems to be running great with the above listed setup.