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Latest News. SEMA Coverage. Lastly, in extreme cases, you'll want to verify the numbers stamped onto the component were the ones stamped into it originally and aren't restamped. The point of this article is to help you figure out how to decode stuff. Engine Code Stamping Numbers All engines are stamped with an engine ID code, consisting of assembly plant code, production date and suffix code.
V8 codes are stamped on a pad just forward of the right side passenger cylinder head. Click here for Chevy Engine Code Listings The engine date must precede the car build date, otherwise something is amiss. Some engine machining operations decking will obliterate the engine ID.
The format consists of divisional identification number, model year, assembly plant designation and vehicle serial or sequence number. In model cars, the serial VIN number of the car the engine was installed in is stamped next to, or under the engine code ID.
Small Block Chevy Casting Numbers
Starting in , the serial number is stamped either above the oil filter, somewhere on the block pad in front of the cylinder head , or on the transmission flange somewhere. Getting serious means more cleaning, deburring, more cleaning, block prepping, and more cleaning to get the block as near perfect as possible. Everything that can be unbolted, knocked out, or pulled out must be removed. It should be mentioned here that an engine stand is an absolute prerequisite to proper block preparation and engine assembly.
These guidelines apply to both new and used cylinder blocks. Fortunately, modern technology has brought new methods of stress relieving blocks and other components so that the dimensional stability of new components remains consistent. Blocks can be vibrated at specific frequencies on a special table designed to ease stress slowly out of the part.
Luckily, the owner of this block discovered these cracks in the valley not that uncommon in small-blocks and through the lifter bores before extensive machine work was performed. A few taps with a hammer will drive the plug out. This plug must be in place for oil to flow to the oil filter. Later model factory engines use a large steel ball instead of the plug.
Chevy Smallblock Decoding
The starter on the left is for the small-diameter tooth flywheel, while the one on the right mates with a large-diameter tooth flywheel. You can tell the difference by observing the location of the mounting bolts. Another important consideration for block selection is the positioning of the clutch-linkage-mounting holes on the left side of the block. These vary, depending on the original application and can cause problems if mismatched in a stick-shift swap.
Solid mounts have been popular in drag racing, but they create torque stress in the cylinder walls next to the mounting bosses. A better plan is to use cushioned mounts and restrict engine movement with a torque strap at the front of the motor. The best overall engine mount is the GM locking mount. On the right is a cushioned mount with interlocking tabs to limit engine movement. Note in the rear cam bearing bore housing there are three holes in the oil groove. The left and right holes feed the left and right oil galleries, respectively. Small plugs with drilled orifices are threaded into these holes to restrict the oil.
Aftermarket aluminum restrictors can also be installed from the rear of each gallery to accomplish the same thing.
The drain holes in the lifter valley can be plugged so that oil is forced to drain at either end of the engine. This is also accomplished by using standoff tubes screwed into each drain hole. The tubes prevent oil from draining, but still allow crank case pressure to equalize. There are variations in the way block casting cores fit together during the casting process and in the way factory machine tools finish the block. One way to check for this is to observe the front cam bore. It should be centered in the machined surface arrows.
The arrows indicate the location of two 0. The tiny hole in the center gallery plug bleeds air from the gallery at startup to prevent an airlock of the front main bearing oil supply. The hole in the face of the cam bore provides oil pressure to the backside of the cam gear. For any performance application, the bores should be finished on a Sunnen CK1 or equivalent power hone. Always instruct your machine shop to use torque plates with head gaskets during the honing process.
Most modern engine shops are well versed in proper block honing techniques. Lifter bores are another good indicator of a dimensionally correct block. The bores should be evenly centered in the lifter bore bosses on the block. Blocks should be power washed at elevated temperatures with good agitation.
3 Suggested Answers
Modern block cleaning equipment can make a block look brand new, and it can reveal any imperfections, flaws, or cracks. Start cylinder block preparation by completely deburring the casting. Remove casting flash that might break away under stress and smooth over areas where potential stress cracks might develop. Larger sections of flashing will require using small grinding stones.
A high-speed grinder makes the job really easy. Work carefully and be sure not to gouge any machined surfaces. Small files are excellent for deburring the edges of main bearing webs and other short, straight edges. Be sure to tackle every remote part of the block including the distributor pocket, camshaft cavity, timing cover cavity, and lifter gallery.
The only place you can skip is the edge of the deck surfaces, since they will be rendered sharp again during the decking procedure. Now you should spend some time running a tap or a thread chaser through each threaded hole in the block. If the hole is a blind hole and it carries some torque e. A bottoming tap can be made from an ordinary tap by grinding off the tip, which is normally used for starting the tap into an unthreaded hole.
If any of the head-bolt holes are pulling out, wait until after the decking operation to repair them with Heli-Coil thread repair inserts. A popular modification at this point is to tap the front three main oil galleries and install threaded pipe plugs. This procedure is unnecessary when the standard plugs are properly installed and staked in place, except in a NASCAR or long-distance application where vibration is severe. However, tapping the passages only takes a few minutes, so you may want to perform this modification even for street use. If you decide to give it a try, make sure you do not tap the gallery passages too deep.
How to Identify a Chevy Engine by Numbers
If the plugs screw in too far, they can restrict the oil feed passages to and from the front main journal. There are two other small modifications that some experienced engine builders make in this area. One is to drill a tiny 0. It should be centered directly above the cam bore centerline and pass into the short oil passage leading from the main oil gallery to the front cam bearing.