It is not apples to oranges. Its physics, especially in a ladder bar car or Caltrac type car. The tire is "wadding over itself" because there is to much bite and not enough valving on the extension side of the shock. If it is a leaf spring car taking bite out is not so easy making valving even more critical. The MORE power a car makes and the faster said car is just exacerbates the issue. It's just physics, power does not change the physics of the issue just makes it harder to control.

My street car responds EXACTLY the same way, on a 10.5" tire running low 10's in Vegas at 3600lbs, as did my Belvedere running even slower. Control of the housing is what you need not more air. You mask the issue with more air because you are not controlling the rear end housing. Cheap shocks will not control the housing at all. Worked on every car I have been around and helped with. Starts with rear set up and shocks. The tires on the dragster have been on it for over a year and have 190+ laps on them.

The OP's car is actually a mid 9 second car, with ladder bars. The air in Vegas is not kind to ET's. I have watched the OP's car make a few passes and will GUARANTEE if he gets better control over the rear end housing with more extension valving the tires will be much happier and the car will be quicker period.

Topics like this really make me miss Monte.......

Al, all my old leaf spring cars would respond(go faster and quicker) to more air when I had let them down to low with 3400 Lbs. + plus cars on smaller tires bias ply slicks like 10.5x29x15 when they would shake from wadding up
Those where mid 11 to mid ten second cars
I've never let the tire pressure down low enough on my ladder bar cars or 4 link car to make the tires wad up like Mikes are 5.5 lbs. is not much air pressure

Cab you gotta have shocks to control the housing at the hit. Otherwise its a bandaid. We have had it down to 5lbs at times(had others lower) and as high as 7 depending on track conditions. But as I have said a few times if you don't have enough shock to control the housing, or if you have to much bite in the suspension not much matters. You need what it takes to get the car up on the tire quickly so it can accelerate quickly. That is based on track conditions and HP. We out 60' every car at our local bracket races by a good deal. Precisely because we pay attention and let the tire, chassis, and converter work as they are intended.

I also agree you want to run as much pressure as you can. I also agree in a bracket car it is much easier to KILL the tire to ensure it dead hooks. It aint fast but particularly in slower cars its consistent. In a faster car killing the tire is not consistent at all. Not saying you or anyone else needs to be at 5.5 lbs. Just stating the basic physics of whats going on and how it is controlled. Difference between a car running low 10's with a 1.4x 60' and a car running those same ET's with a high 1.2x 60'. All about efficiency

You are correct on that, my old cars had stock 50/50 shocks on the rear back then
We do learn, if we try hard enough and keep our minds open for help from others like you