340 j heads?

Oh yes,
I remember those heads they went to RamHi4X, they still had the 1.88 and 1.60 valves. On my bench and it's a bit stingy on flow and this is what they flowed, as gasket matched and bowl blended. I'm also adding a 675/318 head for a reference

lift.........Int........Exh...................318 head W/1.78/1.60 open early style
.100.......84.........79...................80..........78
.200......141.......115..................131........115
.300......197.......144..................190........155
.400......221.......188..................212........198
.500......238.......199..................214........204
.550......241.......203
.600......239.......207..................214........207

He was only using a mid .500 lift cam so I made the low lifts as strong as the heads would allow. With a gasket macth and bowl blending. The guides weren't narrowed or thinned.

This what the heads flowed as recieved, but like I said my bench is stingy.

lift........Int.......Exh
.100......78........71
.200.....125......105
.300.....188......127
.400.....209......137
.500.....221......140