My engine came back from the builders 93 lt1 mild cam ported polished all that fun stuff. after putting everything together car wont start. I pulled #1 plug and checked spark it seems to be sparking at the bottom of the compression stroke. The builder said the distributor is 180 out. Cant be it is keyed into the cam gear only one way it can go in, so I pull the timing cover dots are lined up pull the gear set to see he put in a cam for a 96 could this be the issue?? possibly a different gring or position for the distributor????

 

The only thing I can think of is that a 1996 has a crank position sensor that the 1993 does not. I don't know if this is the root of your problem though.

One other thing, I could be wrong here but I believe the 1996 has the longer dowel pin on the cam and drives the opti. You will either have to hammer the pin all the way in or remove it. I think this could be your problem. The 1993 runs off the timing gear.