[74stang2togo]

Originally Posted by bornfairview

Wow, what kind of carb are you running to have it set for 6 psi? Must be a one barrel for an import 4 CYL

The stock 2-bbl. carburetor was set at the factory for 5-6 psi, and the factory fuel pump doesn't put out more than that.

My Edelbrock 600cfm 4-bbl. is set there as well, as per the instructions that came with the carburetor.

The only carbureted applications that should see more than 7-8psi maximum are full-on race applications on big-block or high-revving V8s. 12psi would be starting to venture into throttle-body fuel-injected territory (TBI systems started around 15 psi and ran as high as 25-30 depending on brand and application); running 12psi on a stock 2-bbl carburetor would have fuel flowing out of the choke towers. (hell, 8psi does that, been there, done that).

Don't take my word for it, scroll to the bottom of the following FAQ from Edelbrock, says right there not to exceed 6.0psi with a Performer series carburetor.

Edelbrock.com - Tech Center - Carburetor Frequently Asked Questions

[nigel]

5-6 psi won't work. It will be starving for fuel. A carb need 7-9. 12 will flood it and cause internal damage.

[74stang2togo]

Originally Posted by nigel

5-6 psi won't work. It will be starving for fuel. A carb need 7-9. 12 will flood it and cause internal damage.

Click on that link above, Edelbrock's carburetors require 5-6 psi. The stock carburetor, using a Chilton's repair manual for reference, requires 5-6.5psi, no more than that.

I didn't pull these numbers out of my ass, I got them from the manuals for the carburetors in question. My factory carburetor worked fine at 5.5psi all day till the day I yanked it in favor of a 4-bbl. Edelbrock, which has also worked perfectly with the same fuel pressure since the day it was installed (still using the stock pump because it's more than adequate).

[RLG34750]

it been a while since i have played with a carb

BUT.......

in most carb application 5-6 is usally the general rule of thought....

take in consider what most regulators and fuel pumps are rated at....

running 9 psi on a stock application will have the carb spitting gas like old faithful......

[bornfairview]

All out race motors? I have a 331 stroker at about 540hp with a holley 870 built from a 800 and a 750 and its a street strip car. It runs at 11 PSI all day.