'chirping' 318

Im having an issue with an off idle chirping noise, almost like the flexplate/converter bolts are loose....but they are in fact tight. It does it in any gear as well. Engine has oil in the pan and its getting to the rockers. Pulls 15" of vacuum. The noise is still there with the alt/water pump belt removed. Crank pulley bolts are tight. Recently installed headers...funky exhaust leak? funky vacuum leak? Dead front pump in the trans? no knocking just chirping.

Specs
Stock cast piston rotating assembly
deck milled .050
mopar '759 cam/lifters
smith brothers push rods
stamped rockers
$10 set of cast rings
reused bearings throughout
stock oil pump
#302 heads
performer RPM
Holley 3310-1
unknown mileage 904 with transgo tf2
stock electronic distributor
modded 67-up headers in an early A