C-1 timing

[Dwight Bedsole]

I have a '58 270HP with high lift cam (2X4s) and would like to know what is recommended for air/fuel ratio and timing. June issue of Corvette Fever had an article that basically said that the tuning spec's of the '50s, '60s and '70s were based on a "forgiving leaded" gasoline and are not appropriate for the reformulated fuels of today. They recommend a full 36 degrees of total ignition advance ( vs 26-30 original spec) with 18 degrees of initial timing ( vs 7 degrees original spec) for high lift. My distributor does not have vacuum advance so my 18 degrees of additional advance would have to come from a "re-tuned" mechanical advance at about 3000 rpm. I would appreciate any suggestions as to what has been found best performing.
Thanks
Dwight

[John H.]

Re: C-1 timing

Dwight -

The original centrifugal advance spec for your 1110891 dual-point distributor (26*-30* @ 3700) is centrifugal only - you add your initial to that for "total timing" of 36*-38*. I had your same setup in my '57 270, and ran it at 10* initial with a verified 26* in the distributor (36* total) and it ran like a top.

I think the author of that article suffers from an instrumentation fetish; it's not all that complicated.

[Tom B.]

Re: C-1 timing

I could accept the 36 total but the 18 initial is nuts. Must be a typo. I doubt that you will be able to push it past 10-12 on 93 octane premium before it starts talking to you. Cranking will be a real problem with that much initial too.