gm good wrench from jegs carb to tbi does anyone have a idea

[young42090]

well i have a 1989 chevy full size blazer i decided to get a gm good wrench. crate motor from jegs. and wanted more horse power so went with the 260 hp but wasnt for my tbi motor is actully for a 85 and under carb. guy at jegs said ya np just get a tbi adapter use original ditrubitor out of my 89 and plug and play. well havent had nothing but problems. i went to set igniton timing and set tdc and dropped distributor in pointing at cylinder 1 and damper set at 0 degrees. i cant even get the motor to idle runs for about 10 second perfect and backfires threw the intake. try retarding dis. as many degrees as i possibly could didnt change anything. has anyone ever done this or have a clue whats wrong here any info would be greatly appreciated. thanks. if u need more info i will give u what u need lol. i also tryed to just send the block back but thats not a option even though i was giving false information. lesson learned.
to all a good day