I have a 1995 chevy silverado k1500 with manual transmission I pulled the stock junk 350 out built a 355 with a 3970010 block flat top pistons edelbrock aluminum performer rpm heads comp cam .447 int .462 exhaust lift aluminum edelbrock rpm air gap intake bored out tbi from cfm tech tbi spacer stock injectors have higher flowing fuel pump after market fuel pressure regulater spring running around 20 psi fuel pressure I'm using an after market tune I paid for before I rebuilt engine it idles decent I can't tell it's running super rich.... when under a load or when stomping accelerator it fires back through intake or sputters bad.... I set base timing at 0 degrees and made sure it matched with the data dash with timing advance wire disconnected.... re connected and everything seemed to be matching up... so to try to pin point problem I disconnected timing advance wire advanced base timing to about 25 degrees left the timing advance wire disconnected and the problem went away... that being said truck had more bottom end power didn't sputter but could still tell it disn't have the power it should... I've been studying and playing with the tune and have gotten no where... if anyone could send me a tune that could get me closer to where I need to be I would greatly appreciate it..... my e mail is drslayer7mm@gmail.com incase I don't get a notification thanks for any help