Magnum headbolts are NOT torque to yield, and I've re-used them several times without any problems. however, on a high compression performance build, I would suggest going with new ARP hardware anyway.

but for a mild build, stock bolts are fine. mine has re-used stockbolts, and it's about a 350-ish hp engine. (285 RWHP)

However, Magnum head bolts ARE different than LA head bolts. I found this out when I ordered a set of ARP hardware for edelbrock heads off Mancini. They arrived with 3 different length bolts. The Magnums use 2 length bolts, 5 long ones down the middle of the head, and 5 short ones for the base of the head below the exhaust ports. When I called Mancini they confirmed that the LA heads use a different bolt set than a Magnum bolt set, and took the opened set of LA bolts back without any problem, and sent me the correct head bolts instead.