1994 z28 t56 manual transmission swapping a 96 engine need help
 

Hi let me introduce myself my name is David I'm out Arizona just got a hold of a 1994 z28 lt1 6 speed trying to make a long story short I bought the car got it to start then it started to overheat fast so I change the thermostat and that fix the problem but it sent coolant through my exhaust so that tell me it was the heads so I took that engine out and took off the heads and it look like they have been running water so the cylinder heads are destroyed so I bought a running 1996 engine I got everything hooked up but it will not start change the Opti got a new water pump spark plugs wires but I did not get the ignition coil could that be the problem but I took it off of my 94 engine and that engine run it was just the cylinder heads so if anyone can help me I will appreciate it

Re: 1994 z28 t56 manual transmission swapping a 96 engine need help
 

The 96 coil has a single connector, 94 has a dual connector. If you kept the 94 PCM and wiring harness, swap the coils (appears you may have done that).

Also, if the 94 wiring harness was kept, the 93-94 Opti harness connector is a different length (short) than the 95-97 Opti connector (long) and won't make contact. Would not be a factor if the new 95-97 Opti has a permanently attached harness that runs from the gray connector on the bracket on the passenger side of the intake manifold. If 95-97 Opti has no permanently attached harness, just an open connector, you need a 95-97 short Opti harness. EFI Connection sells them.

What brand Opti did you buy? Most of them are Chinese junk, and can be faulty right out of the box. Reman AC Delco or Petris Enterprises are the way to go.

You would also have a mismatch on the knock sensors. 94 PCM is looking for a 4 Kohm knock sensor, but sensor in the 96 is 100 Kohms. Swap sensors. But that mismatch won’t prevent the engine from starting.

From Shoebox - engine swap differences:

http://shbox.com/1/4th_gen_f-body_ye...onversions.pdf

94/95 coil wiring and 1996 coil wiring:

http://shbox.com/1/95_ign_system_schematic.jpg

http://shbox.com/1/1996_ec_03_ign_system.jpg