Trying to decide what plug to use on the 348 c.i.. Casual driving, no pedal to the metal.Checking various types, noticed they have different plug each, 3/8 or 3/4. Can't find anything in shop manual except for gap(35) & thread size(14mm). Without looking, I think I'm running AC, 43,44, or 45, Im not sure. Thinking of transporting car to Florida(The Villages) in Oct. Will Florida weather affect choise of plug? Suggestions?

I just looked in a Champion catalog and it said 1958-61 Chevrolet 348cu.inch 3/8 plug RJ12YC and for 3/4 plug N11YC.
Delco catalog didn't list a '58 Chevrolet with 348. It said '59-61 348 44N.
I don't know if recommendations may have changed since these catalogs were printed.
I don't see why being in Florida would change anything. My 2 cents.
Neil (Canada)

I see there was an early and late on the '58 Plugs (348) as far as size. The early ones 3/8 reach and the late ones, 3/4 reach.The early ones for 1958 take the AC 44.
Neil (Canada)

I'd go with AC44's. UNLESS you've been experiencing plug fouling with your limited high rev driving. If your plugs are fouling quickly, move up to the hotter 45's. Good chance that will eliminate/reduce the plug fouling, even with your typical slow speed/low rev driving.

I agree Fla weather shouldn't have any impact on the plug situation.

Bill.

I'll go with the AC44. I know that Advance Auto & Auto Zone don't carry AC. I'll star checking around before hitting the catalogs.
Thanks

Have an early '58 so I'll go with the AC44.
Thanks for the reply.