'98 PCM with 85mm MAF???
#4
+3, I have a 98 W/ 85mm & ported LS6, no trouble @ all. Just make sure that the MAF table is updated to the 85mm MAF. Will say that the tuner must interpolate the top end of the table. Table peaks @ 11250 HZ; so, generally the highest 3 or 4 table variables up to 11250 HZ are averaged for the measured flow.