The 360 came out in '71. 340/360 heads were open chambered and cc'd between 68-75. 68-72 most of the 340s had the 2.02 intake valves and all340/360 heads had 1.60 exhaust valves. The exhaust ports and intake ports were the same. The 360 had 1.88 intake valves....the only diff.
In pre 73 340s they had forged cranks and pistons that sat out of the hole hence the higher compression. After 72 the 340's pistons sat in the hole that lowered the compression and also used a cast crank.

What year is your 340 mopar_man?.....also check out moparts.com all the mopar info you will ever need.