Power To The People
What To Look For When Buying Pre-Owned Power Parts
From the February, 2009 issue of Chevy High Performance
By Bob Mehlhoff
Photography by Bob Mehlhoff, Jeff Smith
Used engines in good condition...
Used engines in good condition can be great buys. This big-block Chevy had low miles and featured an Edelbrock dual-plane intake. There are many ways to check an engines condition. If possible, run a compression test. Otherwise, remove all the spark plugs and check their condition. Next remove the oil filter and check the oil for unusual odors, water, or heavy sludge. See if the engine will spin by turning the balancer bolt with a wrench.
Used cylinder heads can generally...
Used cylinder heads can generally be assumed to require new valves, guides, seals, and springs. The cash outlay may exceed the price of some new cylinder heads, such as GM Vortecs, which flow better than many reworked stock heads.
Weve seen used Holley...
Weve seen used Holley carburetors go for as little as $20. If you can quickly decipher the Holley part number code, youll be ahead of the game. Also check the carburetor baseplate for cracks and worn throttle bushings, and remove the float bowls to check for missing parts.
When inspecting used rearend...
When inspecting used rearend gears, check the teeth for damage and examine the coast side to make sure no abnormal wear exists. Also inspect the threads on the pinion gear for damage. To verify the ratio, check the ring-and-pinion tooth count stamped on each gear or count the teeth. To determine the ratio, divide the ring gears tooth count by the pinion gears tooth count. For example, 41 ring-gear teeth divided by 11 pinion-gear teeth would indicate a 3.73:1 ratio (41 ÷ 11=3.73).
The terms 10-bolt...
The terms 10-bolt and 12-bolt refer to the number of bolts retaining the ring gear to the carrier. For outside identification purposes, the rearend cover has a matching number of bolts retaining it. This carrier is for a 10-bolt.
Some parts should never be...
Some parts should never be purchased used. Of these three parts, only the used windage tray should be installed in an engine. This is because the timing chain will stretch after use and oil pumps are inexpensive to replace new.
Flat-tappet lifters should...
Flat-tappet lifters should never be purchased used because they form a wear pattern specific to each camshaft lobe. However, most roller lifters can be reused. Just make sure theyre in good condition and that theyll fit your application. Most small- and big-block roller lifters are not interchangeable because the distance between the lifters is different. Also note the offset pushrod position on the lifter on the right.
Posi units are typically rebuildable...
Posi units are typically rebuildable for a reasonable cost. This 3.08 set incorporates an 8.50-inch ring gear and came from an 80 Trans Am found in a local wrecking yard.
When searching for an automatic...
When searching for an automatic transmission for your Chevy, make sure it has a Chevrolet bolt pattern. This transmission will only fit a Buick, a Pontiac, or an Oldsmobile.
This transmission with the...
This transmission with the vertical side flange will only fit a Chevrolet. Some 80s TH200-4R automatics are designed with a dual bolt pattern that fits Chevrolets, Oldsmobiles, Buicks, and Pontiacs.
Used headers in good condition...
Used headers in good condition can be a great bargain if they fit your car. Before shopping for used headers, determine what part numbers your car needs by looking through header catalogs or by going online. At least remember to have the seller tell you what his headers fit before he knows what kind of car you have. Always inspect the mounting flanges for straightness and tube condition.
If youre shopping for...
If youre shopping for a flexplate or a balancer, look closely for balance weights. This harmonic balancer and flexplate came off an externally balanced 454ci big-block Chevy (note the added balance weights) and differs from a smaller- displacement big-block that is internally balanced and uses a flexplate and harmonic balancer without the added balance weights.
Before buying a used block,...
Before buying a used block, its best to check the bore with an inside micrometer. To really be sure the block is in good condition, take it to a machine shop for a Magnaflux crack test.
Used wheels can make your...
Used wheels can make your car look really cool for a fraction of the cost of new wheels. Just remember to first measure backspacing and ask others with cars similar to yours what sizes fit.
Used torque converters should...
Used torque converters should generally be avoided because they may be worn out, contaminated with metal debris, or have a mystery stall speed. A contaminated used converter can deliver damaging metal fragments into your transmission and cooler.
A used four-speed transmission...
A used four-speed transmission can be a good buy if its in decent condition and will easily fit your application. This transmission is a late-model Super T10 with a fine-spline input shaft, but it uses a TH350-style slip yoke. To install it in most early Chevys, the clutch disc would have to be replaced, the driveshaft shortened, and the cross member moved rearward and possibly modified. Finally, a shifter compatible with the transmission mounting and body style would be required. Before buying any four-speed, always remove the side cover to inspect the gears and fluid.
An intake manifold with this...
An intake manifold with this much corrosion at the thermostat would be a poor choice. Even if it could be repaired, it wouldnt be worth the expense.
These handy books Chevy...
These handy booksChevy Suffix Codes published by MSA-1...
...and Chevrolet by the Numbers...
...and Chevrolet by the Numbers from Bentley Publishersare excellent sources of information about factory parts and applications. There are also some great parts-locating guides by The Garden of Speedin.
Before laying down your hard-earned...
Before laying down your hard-earned money, make sure that rearend is really a Chevy piece. This rearend is a 10-bolt from an Oldsmobile and features an inspection cover with cutouts on the sides.
This one is a 12-bolt from...
This one is a 12-bolt from a 67 Chevelle and has no cutouts on the inspection cover.
Building a high-performance car that runs hard and sounds cool takes knowledge, parts, and some money. But as any seasoned hot rodder can tell you, the real performance challenge is getting the most power for the least amount of money. Pre-owned power parts offer the opportunity to add that extra performance at fire-sale prices. But whether you get them from swap meets, classified ads, the Internet, or your buddy down the street, locating a deal on used speed equipment is not only about price, but also about determining if the parts you find are really what you need.
Knowledge Is Power
Shopping for used speed parts can be fun, but first you have to arm yourself with plenty of information. Remember, the goal is to know more than the seller, otherwise youll be at a disadvantage. Fortunately, information about performance parts is now easier to find than ever before. By simply consulting catalogs, visiting manufacturers Web sites, and reading hi-perf car magazines, you can find the part numbers and photos of the parts that interest you.
The appearance of used parts offers clues to their past and may affect their future performance. Headers with heavily dented pipes or intake manifolds with severe corrosion are obvious clues. If youre shopping for electrical items, like a cooling fan, then check the motor by connecting it to a 12-volt source. Remember, you must ground the motor back to the battery to complete the circuit. Some electronic parts, such as ignition boxes, alternators, and tachometers, cant be tested until theyre installed, so you might want to avoid buying these items used unless you know their history.
Used transmissions, carburetors, and posi-traction units at bargain prices are only good buys if they can be rebuilt and fit your application. Check inside for hard part damage, excessive metal debris, and fluid condition. Before buying a used automatic transmission, make certain it fits a Chevrolet. Over the years, GM has built thousands of automatics with bellhousing bolt patterns designed only for Oldsmobiles, Buicks, and Pontiacs.
Dont Be Fuelish
If youre looking at a used carburetor, ask the seller if you can partially disassemble it to check its condition and to make sure no one has drilled holes in the throttle blades. If a carburetor with this modification is installed on an engine with normal manifold vacuum, it will be difficult to adjust the idle speed below 1,000 rpm.
Shopping for a used engine (even as a core) requires special care. Bore condition and size, block soundness, machined surfaces, and displacement must all be verified. Although it may be easy to determine that a used engine is a small-block Chevy, determining engine size can sometimes be challenging. The first step is to read the casting numbers located at the rear of the block on the >> driver side. For example, a small-block with 3970010 cast into it may be a 302, 327, or 350, all of which had an original bore size of 4 inches. In this case, the engine code, stamped on the passenger-side front deck, can identify engine size if the year of the block is known and the deck has not been resurfaced. To learn more about this, consult an engine identification book, such as Chevrolet by the Numbers, by Alan Colvin, or Chevy Suffix Codes by MSA-1 books (see Sources).
Bargains on used cylinder heads are often easy to find, but be careful that the heads have not been resurfaced too many times and arent cracked. If your engine accessories mount to the cylinder heads, youll need heads manufactured with threaded accessory bolt holes.
Keep in mind that many brand-new cylinder heads can be purchased for about the same price youd pay for used heads. For instance, Chevrolets Vortec cylinder heads (PN 12558060) flow much better than even ported stock cylinder heads and are available new for under $500. They already feature hardened valve seats for unleaded operation and come with a warranty. Just remember that these heads require a special intake manifold too.
The Buddy System
If youre new to the parts-hunting game, or you just want someone to help you look, bring a friend who has knowledge about performance parts. If for no other reason, this makes the process fun. But the most important thing to remember when shopping for used parts is to think ahead and learn as much about what youre looking for as possible. That way youll be well prepared to get the most performance for your dollar.
The Garden of Speedin
Summit Racing Equipment
P.O. Box 909
"BMW 3 Series Service Manual: 1992-1998" and "Comp