I'm stumped and need some info incase there's something I have missed.
2004 Cavalier 2.2 vin F Manual Trans

Timing chain went south and had to get another motor. Found a 2.2 out of a 2004 Malibu Classic with the F Vin. Dropped it in and the fuel rail that was on the Cav originally wouldn't seat down into the injector holes far enough to seal which caused a runaway condition. I "modified" the mounting tabs on the block and rail to allow the injectors to sit down into the holes. Problem I'm still having is that the motor is still falling on it's face at about 2500 rpm and backfiring (through the exhaust), and it also has been popping back into the manifold and hesitating when trying to start the engine. The injector rail that was on the Malibu did look different from the one that is on the Cav, but I didn't think that should matter as long as the fuel injectors are seated/sealed. The cavalier looks like a cast tube with injectors attached to it, and the other looks more like stainless pipes that screw on the injectors if memory recalls correctly. I really don't think that the injectors are the problem anyways, it acts as if the motor's timing is off. I've also tried 2 other coil packs/ignition modules off of other salvage vehicles and it didn't really change anything.

All this to ask, are there some differences between the malibus and Cavaliers that I was not aware of? The Hollander interchange showed the Malibu Engine to interchange with my Cavalier. Hopefully someone can shed some light on this one and help me get this thing going again. Thanks in advance!