It has brand new timming set. Nothing specail when installing, just lined up the two dots. Timming is only at 12deg. I'll dubble check that too. It made this hug backfire out the exhuast once trying to start it back up the first time, don't think it harm'd anything though. Sounded like a M100 going off. It was enough to losen the cat-back off a little. The only thing i could think was, some of the injectors got droped and had to use 3 used ones I had laying around. There white top, so I'm thinking there not the same lbs. They came out of a 86 5.0 non-HO t-bird. We're gonna buy a new set aways, that may be the problem right there.