Why is my hood scoop so low?

Question:

I am restoring a 1970 Torino Cobra with a 429 Thunderjet engine. I believe it is a pre-1974 engine. The engine in the car is the third 429 I have installed in it and that was done in 1978. It has a 700 series Holley carburetor on it, as well as a regular Ford air cleaner and intake.

I have a 1970 shaker hood scoop. You guessed it... I decided to see what it would look like on the current engine that’s in the car.

I have two hoods for the car. I got a template from Dearborn Classics and used it to turn one of the hoods that I have into a Cobra Jet hood. After swapping air cleaners, the shaker hood scoop sits halfway down in the hood. The hood line is through the middle of the words “Cobra Jet”.

What is the difference between the 429 Thunderjet engine vs. the 429 Cobra Jet? (I know the cosmetic differences between the Cobra Jet vs. the Super Cobra Jet engine.) Were the heads that much different? Was there a different intake? Did the 429 Cobra Jet have a factory high-rise manifold that would make the scoop clear the top of the hood? I have always thought the same 429 block was used on both types of engines.

Answer:

The 429 Thunderjet and 429 Cobra Jet both belong to what’s called the 385-Series family of Ford engines, so they are certainly very similar to one another. There are, however, a number of important differences.

The Thunderjet engine had two-bolt main bearing caps, cast iron crankshaft, forged steel connecting rods with 3/8inch rod bolts, cast aluminum pistons, hydraulic lifter camshaft, 2.08-inch intake and 1.66-inch exhaust valves, non-adjustable rocker arms, and cast iron intake manifold.

In contrast, the Cobra Jet had four-bolt main bearing caps (with the exception of some early model year 1970 versions), 2.25-inch intake and 1.72-inch exhaust valves, and adjustable rocker arms (on the earlier version of this engine).

The Super Cobra Jet was further beefed up with, among other things, a larger four-barrel carburetor, forged aluminum pistons, mechanical lifter camshaft, adjustable rocker arms, heavier capscrew connecting rod hardware, and a very large four-barrel carburetor.

And most relevant to your question, the Cobra Jet and Super Cobra Jet both had a different intake manifold than the one used on the 429 Thunderjet.

The Cobra Jet intake is substantially higher than the Thunderjet intake, which explains why your shaker hood scoop sits too low.

You need to change the intake manifold or use a spacer to get the air cleaner assembly up higher.

According to the experts at Dearborn Classics (www.dearbornclassics.com), the Cobra Jet intake manifold is not being reproduced so you will have to hunt around for a good used one if you choose to go that route.