FWIW, most of the bolts on my engine don't seem to be factory specs. I remember the guy I bought the car from bought it from a kid for $400 and it wasn't running. He pieced it back together using whatever bolts he could, and it has run pretty decent from then on out. Every time I take the top end apart I have to try different sockets to see which one fits each bolt. I think the 12 or so long intake bolts are consistent but the others don't seem to be.
Also, when you put it back together, make sure that bolt is TIGHT w/ that ground strap between it and the intake, or your car won't start. I think that was one of my screw ups before.
Last, if you're like me and some others on here...those intake brackets are pretty useless (except the one for the grounding strap). I leave the rest of them off--makes tearing the thing apart easier the next time.