I believe the 1300 series are polished. Mine runs the 1224 Pac.. When swapped at 200 passes zero pressure loss. Current set has 300 passes. Stainless 2.25 x 11/32 intake valve. 285/292@.050, .800. 7100 every pass.
Doug

Last edited by dvw; 12/16/20 10:34 AM.