Torquing fasteners is a method that's used to achieve a preload without actually measuring the preload. This ensures that the bolts or nuts are tight enough to hold the parts in place, but not so tight they're overstretched. The proper torque specification for a fastener depends on the material of the fastener, how it was heat-treated, and how large it is. A factory 11/32-inch rod bolt requires 35 lb-ft of torque while a 3/8-inch bolt takes 45 lb-ft. Change to an American Racing Products (ARP) 3/8-inch rod bolt and the torque specification jumps to 50 lb-ft because the ARP fastener is stronger.
There's also a dramatic difference in required torque when tightening fasteners with various forms of lubrication. In the ARP catalog, it specifies that its 170,000-psi tensile-strength 3/8-inch studs be torqued to 50 lb-ft when using engine oil, but only 35 lb-ft using ARP moly lube. However, both torque readings should deliver 9,200 pounds of preload.
The bottom line is to follow our recommendations unless the aftermarket fasteners you are using come with directions that deviate from our chart, in which case, the specs in the directions should be adhered to.
All V-8 Chevys are the Same
We've included all Chevy V-8s in this article. All of them share bellhousing and motor-mount patterns, so you can swap a 400ci engine from a station wagon into a truck if you want to replace a wheezing 305. This info is also provided so you'll know what was produced in order to avoid less desirable engines.