Gwatney Performance L86 intake swap: https://gwatneyperformance.com/produc...

Also check out "Tech Talks" on the Gwatney site...good info

another swap vid:    • L86 Intake Swap w/ Katech Ported Gen ...  

L83 to L86 intake and TB:
12639087 L86 intake manifold
12678223 6.2 throttle body. (cheaper alternative 12678312....see comments below)
12626354 manifold gasket (8 req)
12639086 6.2 throttle body gasket
12650610 PCV tube

Torque specs:
intake 44in-lbs first pass / 89in-lbs second pass
throttle body to intake 89in-lbs

Uni valve cover breathers UP-104