How do you change intake manifold on 1968 Chrysler Newport 383?

Answer 1

It unbolts fairly simply. There are no coolant passages like a small-block. It does have an exhaust gas passage in the center to bring hot air under the carbureuter for anti-icing and faster warmup. Be sure to blow away any dirt around the sides against the block before removing. The intake gasket is a single piece of large sheet-metal called the "valley pan" that sits under the intake manifold and includes the gasket. You might be able to leave it in place and re-use. I never tried since always removing the heads. You would have to insure no dirt gets between the gaskets and the heads and that the exhaust openings are cleaned. If you remove it, steel bars clamp it to the front and rear of the block. A new valley pan usually comes with installation instructions. I recally using RTV along the edges and a little high-temp (red) RTV around the exhaust holes, but there might have been a tube of sealant in the box. Once I tried adding a special gasket with screens that claimed to breakup fuel drops for better mileage (J.C. Whitney). The extra thickness made it hard to get the bolts aligned. This is also a problem if you mill the heads. In a worse case, you might have to mill the intake manifold to match so the ports still align.