As far as the 3/8"-16 bolt holes for the intake, It is very odd. I can say that the 2 bolts that stripped were both on the Driver side head. All other bolts (8 others) torqued down with no issues at all. I am thinking it was just a bad thread job and with aluminum threads.... they just stripped.
Not taking any chances, last night I got 3/8-16 steel helicoils. I drilled out (carefully and nervously) the bolt holes as instructed. I stuffed balls of painters tape in each drain hole in the valley of the block as well as a piece over the distributor hole. I used tape instead of paper so any metal shavings would stick. I made sure when I drilled out the existing threads that I did it in steps. Each time I pulled out the bit to make sure I wasn't going any deeper than the original hole. Then I tapped each hole for threads as I went for the Helicoils. After the drilling and the tapping, I used a shop vac to suck out the hole of shavings as well as anything that dropped onto the valley (block). I was meticulous about this, and even when I was done for the night, I left the tape covering each hole in the block until I can come back and scrub it out with soap and water.... and sucking that up with the shop vac.
As of right now, all 10 holes have the helicoil installed. I have longer studs coming today in the mail, and 12 point ARP nuts to fit. Rather than using the grade 8 bolts, I am going to use studs with ARP lube. I figure if I bottom out the stud and then just torque the nut, I wont run into any stripped threads. I also ordered studs for the carbs (EFI throttle bodies). Holefully that will be the last time I need to use Helicoils.