I don't know of any aftermarket systems that convert the setup over from vacuum to electric servos, so I haven't tested any to see if they are any good. Your system is very simple in that it's only a vacuum, easy to repair, and it's easy to get parts. I know firsthand that Ames Performance tests each vacuum switch before the company sells it. However, other GTO parts suppliers in this issue have free catalogs, toll-free phone numbers, and sell repair parts as well. Do a quick checkup of your system to see what you need.
Start the GTO and let it build up vacuum. Then shut it down to see if the headlight covers begin to sag. Also listen near the unions and connections to see if you can hear a leak. Listen under the dash to learn if the headlight switch is leaking as this is common. Check the source of the vacuum, the two lines, the unions, switch, and the vacuum "biscuits" in the headlight assembly to ensure positive connections.
All in all, they work well when the connections are good. Age and cracked rubber is the enemy. With a little patience, you can probably find the problem and correct it more quickly and easily than converting to an electronic unit.
'69 T/A Paint CodesI was wondering if you could help me out on a paint code. I'm repainting my '69 T/A, and I want to use the correct Dupont paint and need the code for Cameo white. Do you know what that code is?Jim LombardiVia Internet
Melvin Benzaquen responds:The Dupont code is 5338 for the basecoat. PPG's is 2058, and the factory code is 50 and 11/WA3967. Dupont's number for the blue is 5327 basecoat. The factory code is 26 and WA4069. PPG's code is 2213.
As always, color-test prior to doing everything to make sure the mixture is correct. The mixing can be affected by temperature, humidity, and the exactness of the mixture application.
Gear Swappin' In Second-GensI have a '77 Firebird Formula with 400 and a four-speed, and I want to install new gears in the rearend to upgrade from 3.23 stock to 3.73. Will the new gear kit fit right in, or will I have to change other parts?Jcrace6Via Internet
Rocky Rotella responds:Your '77 Formula has the same rear axle as most '71 and all '72-'81 Firebirds. It contains an 8.5-inch diameter ring gear that is fastened to the carrier with ten bolts and is commonly referred to as an "8.5-inch, 10-bolt" rear axle. There were, however, two different carriers used in this application: one specific for gear ratios of 2.56:1 and numerically lower, and another for ratios of 2.73:1 and higher. Since your '77 Formula was factory-equipped with a gear ratio of 3.23:1, you'll have no problem installing the 3.73:1 gear set into your original rear axle.
There are a few companies currently manufacturing gear sets for the GM 8.5-inch, 10-bolt rear axle. Because each manufacturer uses a different helical cut on its ring and pinion, it's nearly impossible to remove all traces of gear whine from some, no matter how many times the carrier and pinion are readjusted. The Yukon Gear and Axle line, available from Randy's Ring and Pinion in Everett, Washington (www.randysringandpinion.com), has consistently offered the quietest operation.
I highly suggest a corresponding installation kit; it will contain all the small pieces that are required for proper assembly. And if you've never performed a gear swap before, consider some experienced help or even professional installation. Even the slightest margin outside the recommended tolerances can lead to an aggravating whine that typically becomes very annoying over time.
What Engine Is This?I'm restoring my '78 Y88 Trans Am. The engine isn't original; I believe it's a 400 made in late '73 for '74. Any help identifying what I have is greatly appreciated.Here are the codes:Car's VIN: 2W87Z8L158894;Engine VIN Stamp: 28N167191;Heads: 6X GM8 8168;Engine ID: XX ;Casting No: 481988;Casting Date Stamp by Distributor: J277;Manifold: GM1 10003385.David S. BauerVia Internet
Rocky Rotella responds:Even with the presented information, I can't accurately determine your engine's original application from its engine code. We know from the block's VIN that the engine was originally installed in a Norwood, Ohio-built '78 Firebird and is obviously not original to your Van Nuys, California-built Trans Am.
Code J277 on the block indicates it was cast on October 27, 1977. Assuming that the "8168" on the 6X heads is actually B168, they were cast February 16, 1978. However, I think you're one digit off on the intake-manifold casting number. The correct number for the '78 four-barrel manifold is 10003395. With this, I am fairly certain you have a complete '78 engine. But after thoroughly searching my references, I can't find an XX code for '78.
The 481988 casting is typically associated with '71-'74 400ci engines. However, Pontiac recast the 481988 block in 1977 for the '78-'79 T/A 6.6 engine. During this particular run, a large "XX" was added to both sides of the block, near its casting number and in its lifter valley. I suspect you may be mistaking one of these for its engine code, which is typically located just below the passenger-side cylinder head on the front of the block. Take another look: I think you might find an X7 or WC. And if you do, you've got a T/A 6.6 engine for your Trans Am!