NGK R5671a-8

Read up about non projected spark plugs. Ngk R5671a-8 are a race plug that is non projected and seems to have good reviews by some members here. My question is will these be a good choice for my 360? It is wild but mild mill. 340 X-heads, KB107 flat top pistons, 292 purple cam, Victor 340 intake, 9.5" FTI 3400-3600 stall converter and 3.91's out back. This in a dart sport. Have been running rn12yc and after it is fully warm it tends to ping/detonate some when getting heavy with the left foot.