What was the octane number that Chevrolet recommended for our BB's? I can buy 101 no-lead, I can buy 110 leaded, and I guess I can mix my own with TEL that is still available. Is there a concensus? I have a stock 400hp 1967 BB. thanks
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Re: Octane number
With the 10.25 comp ratio in the 400 you should be able to run 93 umleaded. If your motor has been rebuilt with stainless steel valves and hardened seats, you should be all set as far as laad goes. Even if not rebuilt, 5000 miles of lead use back in 67 treated the seats and valves to enough lead for the life of the motor.1969 Riverside Gold Coupe, L71, 14,000 miles. Top Flight, 2 Star Bowtie. -
Re: Octane number
Hi Dave:
Chris is exactly on target, my 69 400 is built to 485, runs on 93 well, if we want to really get into it a little booster is required. The 101 should be more than enough.
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Re: Octane number
The guys here are right on target, today's method of rating octane is different from what it was 'back when...there used to be two accepted systems, motor octane and research octane, both were used for advertising, altough the results differed by several (more than 5 or 6) points is used on the same batch of gas. The feds a few (more the 15) years back standardized on averging the results between the two, which had the effect of lowering everybody's advertised results without significant change to the product. Just a lot of eople who couldn't understand why they couldn't buy "old 104" at the pump. Then came no lead mandates and vapor pressure changes and reformulated gas...Comment
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