February 2011 Chevy High Performance Q&A

Luck, Where Preparation Meets Opportunity

Kevin McClelland Dec 30, 2011 0 Comment(s)
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We’re sure you work on your fair share of unique vehicles: officers’ cars, fueling rigs, equipment movers, and airframe tugs. This gives you a wide experience base for working on just about anything. Don’t ask us to talk you out of an LS engine swap for your little G-body. That is one sweet conversion that really upgrades the performance and driveability of your Monte into the 21st century. The price of engine and transmission combos out of wrecking yards has really made the swaps affordable. You can pick up 5.3L engines hooked to a 4L60E for reasonable prices. You can even step up to 6.0L truck engine combos for not too much more money. These engines will run for a couple hundred thousand miles before they need major overhauls. The performance bolt-ons are everywhere, and the swap kits on the market make the install painless. Check with Muscle Rods for a very nice swap kit that comes complete with engine mounts, a trans crossmember, and headers. The LS swap will give your car much better fuel economy than just an EFI swap on your Gen I small-block. You can buy the engine and transmission with the complete engine and transmission harness and integrate this wiring into your Monte. The electrical conversion will be the toughest part of the swap. Again, there are tons of people out there who can help. Check with the folks at Street and Performance for anything else you may need for your swap. From engine mounts to engine accessories to help with calibration and wiring, they have it all.

Adding the Holley Avenger EFI is also a very nice upgrade. With either the swap or the Avenger EFI you’ll need to upgrade your fuel system to a high-pressure system so that point is moot. It’s basically up to you. How much time do you want your Monte down, since you want to be screaming down the road with the T-tops off? The engine swap can turn into a longer project, depending on your goals. If you pick up an installable engine and transmission combo, you could knock out the swap in a month or two. The fuel-injection system swap could be a weekend if you play your cards right. Again, we’re not going to try to talk you out of the swap. Both are very viable upgrades to your car. Hope we’ve helped you in your decision.

Sources: brphotrods.com, holley.com, hotrodlane.cc

EGR Feed

I purchased a ZZ4 crate engine from GM, and on the manifold, in the plenum under the carburetor, there are two portholes. Are these holes supposed to be plugged up, or do I leave them alone? They are under the carburetor, and I wasn’t sure if they would let any fuel get out of the manifold. Thanks!

Staten Island, NY

The holes you see in the floor of the manifold plenum are the ports that introduce exhaust gases into the intake manifold when using an EGR valve. When the ZZ4 engine package was in development, it was originally designed as an emissions-legal engine swap package for third-generation Camaros and Firebirds by GM Performance Parts. This engine was a direct replacement for the LG4 and L69 carbureted 305-cid engines that were originally installed in these Camaros. Developing this package, we didn’t know if we were going to need an EGR valve to meet California emissions standards. The ZZ4 engine is equipped with L98 Corvette aluminum heads, which do not have an exhaust crossover to feed the EGR plumbing in that manifold. It was our intention that if we needed exhaust for the EGR, we would feed it externally from a fitting in the passenger-side exhaust manifold. Luckily, we were able to design the camshaft in a way to reduce NOX emissions and not need the EGR system.


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