Re: Thunderbolt engine

Posted by Owen_Dyneto On 2008/9/9 11:12:03

TW, is the casting date on your head also 1951? I may easily have been incorrect thinking that 1953 or so was then the trademark began to be used. But as others have pointed out, many cars still have original engines but have had cylinder head replacements over the years that I don't think that's a reliable indicator. But it seems we can either find out thru the Patents and Trademark Office when Packard registered "Thunderbolt", or just start collecting casting dates on heads that have "Thunderbolt" cast into them. Sounds like a fun little project for someone to collect data on.

My 1948 Custom 8 had a replacement 356 head with a 1951 casting date (factory replacement with 14mm spark plugs) and doesn't have the Thunderbolt on it so I'm inclined to think the Thunderbolt trademark was later than the end of the 23rd series.