Not long home now from a day out to fix something that has bugged me for a while now. My new engine had a harmonic vibration at certain speeds, and I could never figure out exactly what it was.....didn't want to start a thread with lots of advice that would make more confusion.
So after sifting through many pages here, FABO and various other forums and websites, I figured out the problem. Turns out I had been led into installing the wrong flexplate on my smallblock 408. I had everything else correct, except the flexplate. This new-to-me information surfaced about 3 months ago, and I immediately scoured the web for the right part. Eventually I found one at Mancini Racing - must have been the only one they had, as the "No longer available" image went up after I had paid.
Package arrived about 10 days ago, and today was the first chance I have had to get it installed. Took it out to my bud's shop...... at a steady but slow pace, and got into it. Job took us a few hours due to high humidity and the sun beating down on the roof making conditions oh so 'wonderful'.
Lost about two litres of tranny juice, which we topped off later on. It was nice to see that it flowed clean and red like it was new. It was a slow job to begin with as the transmission casing was still very hot. So we worked around the other parts as they cooled off.
The road test around the block and eventual drive home proved the problem has been solved. No vibration at all now. And all for the sake of the wrong part.
That'll teach me to take note of veterans of the Jalopy Journal and such papers....
Measurements taken today were made in 'Eagle Beaks' and 'Washing Machines' (12 x Eagle Beaks to the Washing Machine)
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New flexplate #10242 is 9/64" thick - and the #10236 @ 1/8" thick (for pre-Magnum)
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You can see below the difference in the 'bite' out of the #10236 flexplate - that's about 3/8"
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