HELP!! Wont start fo break-in!

I just got my stroker dropped in my duster, and I'm trying to start it to break it in. It cranks slow (sounds like dead battery). The battery is reading 12.6 volts, and as an added measure when I went to crank, I hooked up my charger in the "start" mode. I only tried a couple times so I don't wipe all the assembly lube off everything, so I really don't know if I'm getting spark, etc. I should be because I just took the other engine out, and everything worked then.