Explorer 4.0 - 4WD.
I replaced the intake gasket on Sunday.
It was quite the bitch too.
Parts were about $60 if you include the antifreeze. It took me about 8 hours to do (never done one before). There was a leak in the back of the block spraying coolant onto the firewall, something that any stop-leak would probably not have handled. Turns out there was a sizeable blow-out in the gasket. Got it replaced and the truck runs great.
About how much did I save by doing it myself?
I had both gaskets on a 5.7 L Chevy replaced for $400 or so. I thought it was a fair price.
Estimator book “time” is 3.6. It was probably about a $400 job.
Thanks Gary, that’s what I was looking for. I guess I won’t make it as a professional mechanic. 
Although I took time to make sure the engine and all components leaving the engine were cleaned (vacuumed and blown off) so no debris fell into any engine orrifice. And I was sure to be careful as to not break any tabs, loose any nuts, bend the wrong part, etc.
Shit, even so, a guy would have to be really crankin’ to get it done n 3.6 hours.
Oh, forgot, is there a multiplier for rust belt (salt in the winter time) and age or mileage?
Not a multiplier, but many shops will add to the book figure to reflect that where appropriate. There are different estimators, and they sometimes have different “times” for the same job, so the figures aren’t cast in stone - they’re a guide.