ftyler: go to site-
www.arp-bolts.com order the complete set from the factory. There will be freight cost involved being shipped from California to you. Don't hassle with your old worn and abused bolts, just toss them. You will have piece of mind and know you did the right thing. Used main bolts that have overtightened and or abused are highly suspect.
Bolt stretch (often referred to as yield) is defined as the bolt stretching to a length beyond where it is able to return to it's original length, when loosened. All bolts have a recommended torque value, based on diameter and material composition. From mild steel (30,000psi)
to aircraft alloy (over 200,000psi) ratings. When this proper torque value is reached, the bolt will have stretched to it's peak length, typically 75% of the yield length/strength. Any more torque and the bolt will not return to the proper length, and is toast. This torque value is determinded by Chevrolet engineers during the design of the bolt and the part and the stresses that the part most undergo.
Too much torque, and the bolt will yield, or permanently stretch and lose it's holding ability.
Too little torque, and the bolt may loosen and may unseat the main cap and cause bearing and or crank damage. This condition also puts great strain on the other bolt on the cap as this will put a sideload stresses on the cap and bolt. As you can see either of these conditions will lead to bolt and/or other part failures.
Point to remember- Bolts are rated in psi (pounds per square inch), which equate roughly to the amount of force needed to literally stretch or pull the bolt apart. As this psi rating increases so does the tightening torque needed to put the proper amount of optimized stretch or (preload) on the bolt. This higher rating will also put a greater clamp load on the part because of the higher load holding ability of the higher rated bolt. Also with the higher rating this means the bolt material is that much tougher and harder, and will be able to withstand greater shock and
thrust loading.
Always clean and chase all threaded holes. All threaded holes in the block should be chased with the appropriate size tap. First use a pick, or small screwdriver and dig the crud out of the bottom of blind holes. Then use a good quality bottoming tap to clean and straighten out the threads. Use care not to remove any material as all you want is to clean the threads to fit your new bolts. Always oil the threads, when you torque any bolts, as dry threads or damaged will yield false readings and fail.
Follow ARP torque recommendations as they may be higher than stock hardware. Piece of cake!
Good Luck!
Think Chevy!
