Electric fuel pump

luckyd

Member
Is there a good reason for not changing to an electric fuel pump on a 322?

The two stage fuel/vacuum pump appears to be needed for different things on this motor.
The only people that seem to have gone this route also changed to disc brakes.

I would like to change to the electric pump for the constant pressure but
some people are advising not to.....but do not have a very good reason.

This is on a 56 Roadmaster.
 

Duco55

Member
Apart from originality I would not know why not. You can even use both. The electric pump will prime the engine better ( and give a more constant pressure) and you probably need to keep the vacuum pump ( for braking assistance).
Succes
groeten
Duco
 

LARRY70GS

Active member
Is there a good reason for not changing to an electric fuel pump on a 322?

The two stage fuel/vacuum pump appears to be needed for different things on this motor.
The only people that seem to have gone this route also changed to disc brakes.

I would like to change to the electric pump for the constant pressure but
some people are advising not to.....but do not have a very good reason.

This is on a 56 Roadmaster.

Electric pumps are very good at pushing fuel, not so good at pulling it. That is why you'll see the pumps mounted out back and low on muscle cars. The pump gravity feeds that way and pushes fuel up to the front of the car. Most guys will sump the tank as well.

I'm not very knowledgeable about 50's Buicks. I know with my 1970 GS455 Stage1, the mechanical fuel pump that comes on the Stage 1 is good for maybe 425-450 HP maximum. What I did for a time was use a Holley Red Pump (self regulated to 7 psi) as a pusher pump in conjunction with the Stage 1 pump. I simply teed it into the rubber supply line near the fuel tank. I attached it to the forward wall of the trunk. The Holley would push through the Stage 1 pump if you wanted to prime the carburetor on a cold start. The Stage 1 pump would also pull through the Holley if it was switched off, but it does impose a restriction on fuel flow which did show up if I tried some aggressive driving with the Holley switched off. It did step up the fuel delivery if I kept it switched on, and I did need it with 500 HP or so. If you do use the Holley, make sure to use a relay. On my car, I had it on a switch so I could turn it on and off.

My current 600 HP 470 uses a Nascar type mechanical pump modified to work on the Buick engine. It is good to 850 HP, and supplies all the fuel I need for mid to low 11 second time slips.
 

luckyd

Member
The brakes are vacuum assist and require more than the engine produces.
The two stage fuel/vacuum pump does this so I guess the only other choice would
be to put in a separate vacuum pump and tank just for the brakes.
I also do not believe you can run both electric and mechanical fuel pumps
on this engine.
 

322bnh

Member
The brakes are vacuum assist and require more than the engine produces.
Don't know who told you this, but the engine produces plenty of vacuum; yours and all other power brakes have vacuum storage too.
The two stage fuel/vacuum pump does this so I guess the only other choice would
be to put in a separate vacuum pump and tank just for the brakes.
not needed; the 2-stage pump supplies vacuum to the wipers only when there is a low vacuum condition like driving uphill with the wipers on.
I also do not believe you can run both electric and mechanical fuel pumps
on this engine.
I do it all the time for the last 30 years on my 55's; I use to prime the carb for easier starting and to remedy vapor lock issues.
 
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