Are Merlin heads good?

They were a good head with the raised exhaust port. They were heavy and like was said, were a good replacement for a stock steel head. I did put a 2.25 valve in mine, but didn’t see any gains in an engine my size. they also eliminate the bolt hole between the intake ports for the manifold.

What are Merlin heads?

World Products Merlin cylinder heads for big Chevys combine large intake runners with open combustion chambers to produce good torque and low-end power. The heads are available assembled or bare; rectangular or oval; with or without intake/exhaust valves; and other options.

Are aluminum heads better than cast iron heads?

Aluminum heads have higher compression, are lightweight and have better ports when compared to iron heads. However, iron heads are usually preferred by daily drivers, since it does not develop problems like aluminum heads over time. Aluminum heads may have to be removed and repaired more often than iron heads.

Are aluminum heads better than cast?

Both types of heads can be damaged if the engine overheats. Cast iron is much more durable. However, aluminum heads are easier to fix. The metal is softer and easier to weld and machine.

Can you run higher compression with aluminum heads?

Remember that an aluminum head is more tolerant of high compression, and all other factors aside, a higher compression motor will make more power than a low compression motor, provided that its unique compression-related requirements (fuel octane, camshaft, etc.) are met.

Will aluminum heads run cooler?

so Al conducts heat from the combustion chamber at about 5 times the rate, which is why you can run higher CR than iron, but it also transmits more heat to the cooling system, and reduces the thermal efficiency of the motor somewhat, causing some slightly less gas mileage, and slightly reduced power at the same CR….

What is the compression ratio for 93 octane with aluminum heads?

Because aluminum conducts (dissipates to the cooling system) heat much faster than cast iron does, you can run 10.5:1 with aluminum heads on 93 octane. For those running 87 octane, 8.7:1 is the most that is safe with cast iron heads, 9.7 with aluminum.

What’s the highest compression for pump gas?

The standard recommendation for street engines running on pump gas has always been to shoot for a 9.0:1 to perhaps 9.5:1 compression ratio. This is in order for the engine to safely work with pump gas, which for much of the country, is limited to 91-octane.

Why can you run higher compression with aluminum heads?

An advantage of the aluminum heads is that because they dissipate heat they are less likely to allow detonation WITH a higher compression ratio.

Whats the highest compression you can run on pump gas?

You can run 11:1 or even 12:1 compression on your pump-gas street motor, but you’ll need this simple advie to make it happen. A four-stroke (or four-cycle) engine is so called because in the process of producing power, the piston passes up and down the bore four times.