Perserving Your Classic Corvette Engine

How to preserve the most important component in your Corvette.

Jeff Bernhardt Oct 7, 2008 0 Comment(s)
Corp_0808_15_z Zz383_crate_motor Valve_covers 2/32

Now we go from the beautiful to well, these valve covers that come with the crate engines. We wanted to use the chromed aluminum GM Performance Parts covers on the ZZ383 like we did on the ZZ4 in the photo at the bottom-right of page 32, but they won't fit beneath the power brake booster. The Vortec heads are just a little taller-enough to kill the deal. The good news is that these Vortec heads support either the center bolt variety of valve cover or the old perimeter mount covers, so there are lots of options to replace these black pseudo-finned Medusa valve covers. Man, are we glad.

Corp_0808_16_z Zz383_crate_motor Adapter_plate 3/32

Let's turn the page now. Suppose you're sitting there reading all this, and you're thinking this is all nice, but I really don't want to deviate that much from a factory, period-correct look. But you do like the idea of a crate engine to thrash-around without the worry of launching a 40-year-old rod out the side of your original block, thereby rendering it totally worthless. The ZZ4 is a great choice and can easily be disguised to look like a vintage Corvette engine. But just to put a little challenge-type spin on it, let's say you also like the idea of a stroker small-block with a full-roller valvetrain and Vortec heads. Well, I'm always pondering the means to an end, so I got with my friend and fellow NCRS member Steve Salley of Salley Tool and Die and presented him with an idea and a model. Steve turned my crude model into what you see here: the first-run of a 6061-T6 aluminum adaptor plate that will allow an early intake to be used with the Vortec heads of the ZZ383.

Corp_0808_17_z Zz383_crate_motor Bolt_pattern 4/32

The plates cover up the four-bolt Vortec intake bolt pattern and leave the six-bolt pattern of the early small-block intake. But, more importantly, they bridge the 0.64-inch increased intake port height to allow for the fitment of an early intake and stock intake manifold gasket. In effect, they become the new head surface. The Vortec heads are a dual-bolt pattern design to also accommodate the early intakes, but only if they have the extra tall ports.

Corp_0808_18_z Zz383_crate_motor Head_surface 5/32

Here's the difference between the head surface of the ZZ383 (on the left) and with the aluminum adaptor plate in place (on the right). If you were to try to install your early intake manifold and gasket set right to the Vortec heads, it would bolt up, but you'd have an incredible vacuum leak.

Corp_0808_19_z Zz383_crate_motor Gasket 6/32

With the intake gaskets in place, you can see the final alignment of components. The shiny aluminum around the inside of the dark gray gasket is not our adaptor plate, but the machined surface of the aluminum head. Our plates follow the shape of the intake gasket. If you want to do some port matching, you'll need to pull the heads.

Corp_0808_20_z Zz383_crate_motor Look 7/32

This is what we're after: an early Corvette engine look from a ZZ383 high-tech crate engine. Lose the lift hooks, replace the long water pump with a correct short one, paint the block, heads, and adaptor plates orange, and you're getting there. Your tach-drive distributor will work with a replacement steel-cam friendly gear, and all your ignition shielding will fit, even with angled plugs.


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