Believe nothing you hear and half of what you see.
It was a full weight T, at least 3700 lbs at that time. It has since been converted to a serious turbo LS that ran 8.3 at BG this year. Not sure of the spring pressures but they held up to the boost. I know the boost was north of 30 psi with the 64/66. It was an old school build that was on it's last legs. The crank ended up with a lot of play which pushed my friend to the LS. He never looked back.That's cool.
Maybe he would be willing to pass on the spring info to the op.
What's the weight of the car?
I know a guy that did the same thing but was on a 4 bolt turbo and the did go 9s it wasn't lite either.