September 2012 Chevy High Performance Q&A - It Has Come In Twos

Kevin McClelland Jul 27, 2012 0 Comment(s)
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I have owned my ’83 for 23 years, and all this time it has been powered by a 150hp LG4 (which is now very tired), so maybe the ZZ4’s extra 200 horses would work for me and make the car a decent performer. The car is a street car. I have put it down the quarter at 16.28 (best time). I would like the car to run at least low 14s or high 13s.

Gary Kilbride
Goodwood, ON, Canada

A. The change in personality when you add 200 hp and a ton of torque to your dead original ’83 Z28 will surprise you. If you’ve read the column for any period of time you will know we have many years with the ZZ4 engine. Yes, the turnkey ZZ4 PN 19201330 is a very mild engine because of its dual-purpose design. It’s a great engine and will impress you on many levels. With peak torque coming at 405 lb-ft, it really moves you around.

Now, the ZZ383 PN 12498772 is nothing to sneeze at. The base short-block was stolen from the HT383, which is a very heavy-duty, purpose-built truck short-block. It’s packed with a 4340-forged steel crankshaft, swinging a 3.80-inch stroke combined with a standard 4.00-inch bore yielding 383 cid. Attached to this bulletproof crankshaft is a set of heavy-duty powdered metal rods measuring out at 5.7 inches long and rated up to 550 hp! Finally, filling the bores are a set of hypereutectic aluminum pistons, which give you great ring seal and quiet operation. Yes, the camshaft is quite a bit larger than the ZZ4, spec’d out at 222/230 degrees duration at 0.050-inch tappet lift, 0.509/0.528-inch max lift, and is ground on 112 centers. This is a great middle-of-the-road camshaft for a 383, not going too large for a fully accessorized Camaro with power steering, A/C, and an automatic transmission. Finally, topping off the short-block is a set of Fast Burn cylinder heads. The ports on these cylinder heads started life as the famed LT4 Corvette cylinder heads that were hand-ported and digitized to create the core boxes for these casting. This gives you an as-cast ported set of heads. Among the 33 inches, ported LT4 cylinder heads, and the larger camshaft is where you find the 70hp bump. For all these reasons we recommend this package for your application.

GM recommends its Vortec-designed single-plane intake manifold (PN 12496822). This is a good choice, but for an all-around great street package, we would top it with the Vortec-designed high-rise dual-plane (PN 12366573), which features a square-flange carburetor mount, and a hot water crossover to preheat the manifold in cold climates like Canada. The Fast Burn heads do not have an exhaust crossover, and therefore in cold climates lends itself to carburetor icing.

You didn’t state if you were going to park your Camaro over the winter. We fought with icing issues with the LT4 cylinder heads and it’s not fun. Be aware that you’ll lose around 15 peak horsepower with the dual-plane design; however, the gain in slow-speed torque and midrange will more than make up for the few ponies you lose upstairs.

To finish off your swap you can drop in a new HEI distributor (PN 93440806). We’re partial to a standard 4779 750 double-pumper Holley. These carburetors will drop right on your engine and perform out of the box. You can reuse all the front accessory drives from your ’83 Camaro. It will bolt right up for trouble-free service. Finally, you’ll need to use at least a set of shorty headers—or if you’re adventurous, we’d recommend a set of long-tube headers. Many would suggest 13/4-inch primary tube headers, but sticking with the torque theme of your engine, it would love a set of 15/8-inch primaries. Check out a set of Hedman Hedders (PN 68469). These feature 15/8-inch primaries, 3-inch collectors with three-bolt flanges, and have D-shaped exhaust port flanges to match your Fast Burn cylinder heads. You will need to complete the remaining dual-exhaust system with 21/2-inch tubing. It’s tough but it can be done. Check with a local muffler shop before you take this on.

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