308 heads

im using all my old 340 set up . ported 308 heads solid comp cams 273 solid rocker shafts portosonic intake ported to match ohhhhh 202intake valves fforged pistons i use this now in my 73 duster with a 4000 dynamics converter thermoquad carb it runs 11.90'sall day with a stock rear suspension i was wondering if i stroked it 4" how this would work . the cam is. intake lift 540 . dur at 50 is255 .exhaust lift 555 dur at 50 is260 e thanks my typing sucks