1991 z28 350 tpi Eddlebrock performer heads. Had a flooding issue bad gas smell. Replaced injectors and flooding/smell is gone. Since then the car has been hard to start when cold. Also I put in a 4.56 gears recently so my rpms or way up so I've noticed that the car kind of bogs and pops or backfires at higher rpms approx 3700 and up. Backfiring is out of the exhaust.
Looking for any insight or ideas of cause and possible solutions
Thanks a lot for any insight