Thread: Deadhead fuel pressure regulator

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I need some guidance. I have a 72 K-20 with a 350 small block, 1406 Edelbrock carburetor and the stock mechanical fuel pump. The engine is running a little rough at idle and the exhaust smells rich. I tested the fuel pressure and it bounces from 8-9 psi (seems high for a mechanical fuel pump).

I searched around for guidance on a deadhead fuel pressure regulator and there seems to be conflicting information. Some say a deadhead pressure regulator will damage the mechanical fuel pump.

What’s the best option for a regulator or should I go in a different direction?

A deadhead regulator doesn't ever stop the flow, but reduces flow to create pressure drop so you're not going to hurt your pump. IMO you can use either a deadhead or bypass regulator, and I've heard some say they simply put a T fitting in the line to the pump as opposed to running a return line to the tank. I like this Holley video for their clear explanations without a bunch of BS - https://www.youtube.com/watch?v=w7rCAreQsto

not sure why the pressure is that high ,especially at idle . my guess is blown power valve .

Originally Posted by K20-Bowtie

I need some guidance. I have a 72 K-20 with a 350 small block, 1406 Edelbrock carburetor and the stock mechanical fuel pump. The engine is running a little rough at idle and the exhaust smells rich. I tested the fuel pressure and it bounces from 8-9 psi (seems high for a mechanical fuel pump).

First, I’m proud of you for testing fuel pressure! I have seen numerous mechanical pumps put out too high pressure. Edelbrock carbs do not like high pressure, while they say 6psi, I never run more than 5psi.

Originally Posted by K20-Bowtie

I searched around for guidance on a deadhead fuel pressure regulator and there seems to be conflicting information. Some say a deadhead pressure regulator will damage the mechanical fuel pump.

I have run deadhead regulators with mechanical pumps, currently I run an electric pump with a deadhead regulator set 4.5psi.

Originally Posted by K20-Bowtie

What’s the best option for a regulator or should I go in a different direction?

Deadhead regulators work well, used by thousands. If you’re have fuel percolation problems that a heat spacer won’t fix, sometimes a bypass regulator helps.

But, remember, no carbureted motor is going to hot start as easy as fuel injection…

just reread and notice you have an edlebrock so no power valve. i would replace the pump. any stock motor will only need 4-5 lbs of fuel pressure .

JMHO;
By the mid 80's (35 years ago) EFI was becoming the norm and we were seeing fewer carbureted motors coming from auto makers. By the mid to late 90's (over 20 years ago) EFI became a Federal mandate and carburetors were deemed obsolete. Soon after auto makers sold off their carburetor related stock to aftermarket suppliers and without the demand manufacturing support dwindled.

Today, most aftermarket parts that support our older/classic cars are manufactured offshore. Unfortunately, without high demand for the parts most manufacturing standards are far less than they used to be. In the case of mechanical fuel pumps for carburetors the demand is low. Usually the offshore fuel pump housings and internal parts are copied closely and in most cases a visual inspection shows little differences. Assembly of the parts is often the failure point, in most cases the assembling entity has no understanding of the use of the product being assembled. Usually, the testing and quality control of these products is simple a look and feel. Meaning, the part looks complete and maybe the pump’s actuation lever is pushed to see if air comes out.

I have seen these mechanical fuel pumps output far higher pressures than any carburetor can tolerate.

Again JMHO, but in todays world, I would NOT run a carburetor without a fuel pressure regulator. PERIOD…