[Voltaire]

I recently re-built and installed a ford 302 in my cobra as well as a new Center Force dual friction clutch, throw out bearing and input shaft bearing. The issue I am having is a vibration that starts around 3800 rpm (not very noticeable) and gets increasingly worse as I go up to 6300 rpm or hit the rev limiter. This is under load running through all of the gears. If the car is neutral and I rev it up there is no vibration. Any thoughts on what could cause this would be appreciated. The vibration isn't horrible but it is annoying.

Drive train details;
Boss Block 302 block, Probe mini dome pistons, Eagle H Beam Rods, Forged steel crank, 50oz balancer, Trickflow track heat heads and intake, Trickflow stage 2 billet cam

Transmission/Rear End;
Centerforce duel friction clutch and clutch disk, billet fly wheel, Lakewood scatter shield, TKO 600, aluminum drive shaft, Strange Engineering aluminum 9” center section 3.73 limited slip