I have never re-used head bolts. I just talked to my friend, who is a ford mechanic and he said that he just replaces the gasket (not the bolts) and it is fine. He has done this on his 12 sec DSM, Turbo Miata and his old supercharged 5.0 Mustang. None of them had any problems.
When I got the HG replaced on my Celica at the dealership, I asked if they were going to put in new HG bolts, they said no. It made me feel uneasy, especially on a F/I engine, so I bought ARP head studs and had them install those instead.
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-Travis
1997 4Runner SR5 V6 4X4 Supercharged Desert Dune SOLD :(
1992 Celica All Trac (AWD-Turbo) #223 of 271 US spec for 1992 FOR SALE
2005 Tundra Double Cab Limited 4X4 2.5" lift 265/70R17 Dueler Revo's
4Runner and Celica Webpage