A single T03 will be way too small on a 302. Especially at that rpm.
Let me give you an example...
My first turbo was a T04E "54". This is a T4 frame turbo, considerably larger than that T3. At 6000 rpm I could only manage 8 lbs with the wastegate pinned shut. I still made about 400 crank hp with this turbo, but nothing like where I'm at now.
Do yourself a favor, and keep looking for a good T4 based turbo. They're out there cheap, you just have to find them. Ebay is a good place.
85 ASC McLaren Capri
79 Pace Car