exhaust manifold bolt spacers- why?

Is there any particular reason why on these LT1 motors that some of the bolts are 3/8-16x1.5 with a half inch spacer, and some are just 1 inch bolts without?

Also on my particular car, there are 3 studs, only one of which is actually used for anything (alternator bracket) - so I may just replace those with bolts. Only thing I can think of is that the studs are there to hold the gasket in place during assembly, assuming the nut is supposed to come off. It looks like it may be permanently attached, though.

The spacers had something to do with thermal expansion. Not sure how much they helped as the rears break off anyways

I will say this, having spacers on the bolts allows you to remove the shaft with vice grips without having to remove the exhaust manifold if it's just the bolt head that pops off. When I replaced my exhaust manifold bolts, I used longer bolts and put spacers on ALL of the bolts for that exact reason.

That's what I was thinking as well, just use spacers for all.

Use grade 8 bolts while you are at it, and put anti-seize on them.

Fred: already in the plan.

Anyone know where to get these steel spacers? The GM ones are crazy expensive. I may try the motorcycle parts place, I think they have those exact things (but chromed.)

Searching online so far hasn't been very helpful- too much noise in the signal.

Not sure on the length, but you can get them fairly cheap from mcmaster
http://www.mcmaster.com/#unthreaded-steel-spacers/=sv8vft

Thanks!