Like someone said, 150 shot is the only way to get that on that budget. On an LS1 you’re gonna have to do the following things;

Intake
Long Tubes
Heads
Cam
Springs

Which of course will also burn any sort of stock LS1 clutch, so add an LS7 clutch to that (and getting it balanced accordingly)

So to get all motor, using used LS6 parts and getting a tune, you’re looking at at least $3000 I’d say $4500 safe side.