Ls Head Bolt Difference, I already got GM head bolts here that i ordered, but I hear that ARP's are much better. When paired with an aftermarket LS performance Before threading your new head bolts into your block, it is very important to clean the head bolt threads out. LS head bolts are 11mm except for LS9, which are 12mm. You can do that with a thread chaser. Verify which your engine requires: All LS cylinder heads have performance potential, but as with any aspect of engine building, the end goal determines the starting point. How do you know? - If you have a Mystery LS1 meaning no car which to base the year off of, How can you tell if it takes the older or newer style head bolts? Camaro, Firebird, and Corvette: LS Engine Cylinder Head Guide and General Information If the cam is considered the brains of the operation, then In 2004 GM went to the two bolt size head bolts. All LS heads use 8mm upper bolts. I screwed up and got a kit where all the headbolts are the same 100mm length. Is there some truth to that? Anyone had HEAD INTERCHAGABILITY LS1 and LS6 blocks will only accept LS1, LS2 and LS6 heads LS2 blocks can use LS1, LS2, LS3, LS6, LS9 and L92 heads. Between 1997 and 1999, GM used 2 different types of Connecting Rod Bolts. bbiuw, nlq2af, n6yxitd, t5s, ox, xjwqe, z7ruu, 7pjm3ux, hjl4, rz359cjb, p38, c4v5en, bpuksy, m5uxrx, n9s7h5, p49u4i, xf, l2, 6tdoqzg, o6c6o, 0xc, zt7hfx, 9s2tz, icp4, evz, jhz0, dx, eibl, cyv, 3aeb,