Fuel - Octane Requirement

[66Hemi]

Acquired the correct Prestolite DP dist for my stock 440-4V. Currently, runs OK on pump premium with stock SP dist.
With DP dist installed, been told I will need to run CAM2 (or equiv) higher octane fuel. Get the need for performance runs, racing, etc.
Q1: Will higher octane fuel be req'd for normal cruising?
Q2: If so, will a fuel mix w/ pump premium meet reqs?
Q3: If so, fuel mix rec?
Thanks!

 

[Fran Blacker]

Think DP dist only lets coil charge longer for a stronger spark.

 

[67 GTX]

Think DP dist only lets coil charge longer for a stronger spark.

Correct. It won't spark twice, just holds the spark longer across the points. I don't think it should make you need a higher octane. You'll get a better burn with what you're putting in there.
Is everything else stock with the motor? 93 octane should be fine for it.

 

[lewtot184]

dual vs single points shouldn't effect octane requirements. different ignition curves in the distributors may effect octane requirement.

 

[miller]

Toss in compression ratio, too.

 

[HEMI-ITIS]

Timing and compression ratio determine octain requirement.Cam profiles with a small overlap can also have an effect.

 

[66Hemi]

Thanks for the info. Much appreciated.
Car: '69 Coronet R/T; #s matched 440-4V, 4-spd. Track-Pak. Unrestored orig ext, int, drivetrain, etc. All NOS. 28K mis

Engine is totally stock. Other than normal tune-up & maint, not been touched.
Had to wonder if adding the "missing link" (NOS Prestolite DP dist) would adversely impact.

BTW:
Timing advanced 35 degrees for the current SP dist. Timing similar for DP dist?

Life @ 5800+' elev can be a bit taxing for that aging lady (and us retired old farts).
91 oct pump premium in this neck of the woods