I have a s4 thats getting no fuel and no spark. I just swaped the motor to a bridgeported motor and all the wiring is correct but im still getting no spark or fuel, the starter isnt even cranking and the battery is a brand new optima red top.

 

No spark nor fuel is usually the ENGINE fuse blown in the interior.

NO and I mean NO action out of putting the key to START is invariably the ignition feed wire disconnected just below the engine fuse box. It's a single black wire and a single connector.

IF it's connected, then go to the pigtails for the ignition switch and pull the plug apart that has a black/white wire and a pure black wire. The pure black is the ignition feed wire coming from where I described above.

I'm assuming the headlighs work, so it can not be the MAIN fuse in the engine bay.

If you have NO lights anywhere, then it's the MAIN FUSE.

 

i have an 87 gxl na i put a turbo motor in and i turn the key to start and everything dies loses all power and have to disconnect battery cable and rehook up would that be the same problem?

 

Sounds more like bad battery terminals or the other end of that battery ground cable is not on good. That negative cables other end should be connected to the long bolt on the starter or at least one of the transmission attach bolts.

Or it could be a bad cell in the battery. Try a batt out of another car if your sure the other things are ok.