84 720 build

[tommy Nadon]

Hey everyone I’m Tommy. I’m rebuilding an 84 720 with 250,000 miles. The truck runs but motor is tired. I am going to rebuild the motor and put a Webber carb. My question is what kinda header can I put on stock head? 

[datzenmike]

Save yourself the trouble and expense. The Z series head was designed for low emissions and fuel economy and is very good at both. It does not flow well above highway speeds and runs out of breath. The exhaust manifold is not restrictive at these speeds so a header won't do much. The Z24 is a great reliable engine with cross flow head, dual spark plugs and hemi combustion chambers but was never intended to be high RPM high horse power. The stock carburetor is a little small so your idea to swap a 23/36 Weber on is sound.

 

Header, the bad..

Expensive for a good one, get ceramic coating for longest life.

Hard to install, they NEVER fit perfectly often needing a dent hammered to clear something.

The gasket or collector comes loose or needs constant tightening

Extra surface area increases under hood temperatures.

Noisy

They rust and look like shit, (several months) eventually rusting out. (several years)

They need to be welded and maintained to get the most life out of them.

Never adds the 5-8% more power advertised. Need counseling to get over the disappointment.

Usually does not have provision for the AIS or ATC systems so not emission compliant if you have testing.

 

... the good

They are lighter than the stock manifold.

 

TIP: don't throw the stock manifold away. This way you have it when you get sick of it.