Engine won't crank over with a single plug in it

[KurtEsposito]

Have a rebuilt 1994 350 LT1 Vin P. I was just supposed to be installing it. When we try to crank it over it will spin free with no plugs in it but if I put a single plug in any cylinder it stops on that cylinder's compression stroke (?).

I have been told by an engine rebuilder that the timing should be set at cylinder 6 tdc, however the person that rebuilt it believes he set it at cylinder 1 tdc.

My 2 questions are:

1) Is it possible a cam being off 180 degrees would cause this
2) I want to rotate the cam 180 degrees but am unsure if this is an interference engine.

Thanks in advance

Kurt

[harner]

Are you sure it's not a weak battery?