December 2011 Chevy High Performance Q&A

Kevin McClelland Oct 24, 2011 0 Comment(s)
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Drum Spindles

Q. My dad has a ’68 Camaro that he bought brand new and it came originally with drum brakes. A few years ago he found company called ECI that makes front disc brake kits that work with the original drum spindles without any modification. The kit number is EC723ACK. He would like to drop the front of the Camaro about 2 inches and was wondering if anyone makes a drop spindle for drums so that he doesn’t have to change his whole setup.

Jared Johnson
Rexburg, ID

A. Your dad is in luck. When modifying the front spindles of either an early Camaro or Chevelle to install ’69-and-up disc brakes, all you have to do is cut down the pad for the drum brake reaction pin. This threaded hole in the spindle must be milled down approximately 0.200 inch to line up with the factory disc brake bracket. We searched for ECI and were able to find a picture of the kit. It uses the factory-style, single-piston OEM caliper with a retrofit adapter bracket bolting to the drum brake spindle.

Digging through the drop spindles offered for first-generation Camaros we found that most of the manufacturers eliminate the bolt-on caliper bracket and forge a caliper mount integrally into the drop spindle. Also, most of them wanted you to use the later-model metric-type caliper, and 10.5-inch rotors used on the later-model F- and G-bodies. Heidts offers a factory-style 2-inch drop spindle that retains the bolt-on-style caliper bracket. Also, the upper ball joint mount is only lowered by 11/2 inches. This helps with handling by giving you a better camber gain curve as the suspension travels through its arc.

Finally, again, when installing factory disc brake on early drum spindles, you must machine off around 0.200 inch from the reaction pin pad. Since these spindles are for disc brakes, you will need to pick up a spacer to bolt between your ECI brake kit caliper bracket and the Heidts drop spindle. This should take care of any bolt-up issues. Enjoy your new stance and the handling the spindles have to offer.


Peanut Plugs

Q. I have a ’72 LT-1 short-block with a 350hp hydraulic cam from GM. The engine has 2.02-angle plug heads from 1972 as well. Which spark plug should I use? The engine is in my street-driven ’69 Camaro. Thank you in advance for your answer! I have six different answers from five different GM sources, including one who says they don’t answer tech questions any longer.

Jim Shelton
Gilbert, AZ

A. Opinions on spark plug heat ranges will vary greatly based on the application and mindset of the expert. Many advisers with racing experience will err on the colder side, and OE-type mechanics will tell you to run whatever the factory recommended. When you start bolting together non-stock engine packages, the plug heat range really doesn’t move that much unless you’re using forced induction or nitrous oxide.

Back in the day, the ’72 LT-1 was a very de-tuned original LT-1. It was equipped with flat-top pistons and 76cc combustion chambers, dropping the compression down to a smog-friendly 9:1 range. The original ’70 LT-1 was equipped with domed pistons and 64cc combustion chambers yielding 11:1 compression! The factory plug for the ’70 LT-1 was an AC 44TS, which was a nonresistor, projected-tip, tapered-seat peanut plug. You said the heads are around a ’72 2.02-inch intake valve, angle-plug cylinder head; those should be the “292” casting “Turbo” head. These were the high-performance, over-the-counter GM heads back in the day. They were all we had to work with to make power. The 350hp hydraulic camshaft was the 350hp 327 camshaft used in many of the ’66 and ’67 high-performance small-block applications.

Now for your seventh opinion. Based on the information you have given us, we’d use a plug very close to the AC R44TS. This heat range is a pretty cold street plug, with most of GM’s applications coming in at a R45TS heat range for small-block applications. The 44 heat range converts to a Champion RV12YC, Autolite 26, and a NGK UR4. Between these four choices, you should be able to find a plug you prefer.


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