Ron, I know exactly what you are saying.

My old combo ran in the 12.40s before it sat for an extended amount of time, 15 years or so. Got the next motor in the car and it didnt feel all that impressive. I really didnt know if it was all that much quicker or not. That motor ran 11.30s. Now I have a very mild combo in the car. After long discussions and logic it should be back in the 12.40-.50 range, but the butt dyno says it feels quicker. So that has me worried. LOL.