My fall.
Two tenths on the tires and it was only a change from Vintage Bias-ply Super Stock formula 1 front tires to Moroso Front runners along with the rear Mc-Creary's to Hoosier QTPs one day to the other with weather almost the same.
The Formula 1's of which were looking almost period correct on my car weighed 23 Lbs each as compared to the Morosos that weighed in at 13-1/2 lbs each. I lost the numbers for the rears though.
The remaining tenth that made up the three tenth loss was found with launch tactics, a little bump on the timing and synthetic Torco engine oil from traditional dinosaur oil.