This is pretty much what I have done. I started at 10 psi. It was spinning a lot.
I had the car scaled because it was pulling right. First pass after scaling was at 9 psi was 1.40 60 ft.
We went to 8 psi, after I talked to Goodyear last week and the 60 ft. dropped to 1.38.
It doesn't seem to be spinning now, but I don't have the video in my possession yet to evaluate it.
A minor jet change picked up the mph.

I am not a chassis tuner at all.
I am trying to get into the 5 second ET range. I guess I can just keep tuning the engine for more power?

Mark