YES, you do need a FPR with an Edelbrock or Carter Carb on a Ford with standard 7 psi fuel pump pressure.

The 351M and 400s factory spec 7 psi on a mechanical pump. My old mechanical pump pumps steady 7 psi unregulated. Those old Mopars and Pontiacs did not have 7 psi pumps. They pumped good volume, but they maxed a lower psi. I remember my '69 Dart 340 had somewhere around 4-5 psi and I supplied a 3310 Holley 780 with it.

Josh ... The Edelbrock / Carter carbs have shorter float arms and smaller floats than a Holley, and as a result a Holley will handle higher pressure.

I've rebuilt and modified many of both. It's not that one is special or not. It's a matter of leverage. You want to use a lever to lift a load. The load in this case is the float needle being forced away from the float needle seat by fuel coming in from the other side, push by a fuel pump with strength measured as PSI. Just like when you choose a longer pry bar to move or lift or tear open a crate, a longer float arm makes it easier for a float floating in gasoline to push the needle shut agaist that fuel pressure. A shorter float arm is going to require more strength used to do the same job, just like there are some guys who can lift, move, or open that crate with a short screw driver while you might need the longer pry bar.

Holleys have both bigger floats that will carry more weight when floating in gasoline ... hence more force available .... and the float arm is longer, thus applkying more leverage against the needle.

There is also the question of inlet needle / seat diameter as a inlet of double the area with same psi will apply 2x force. But the Holley and Edelbrock both are pretty close in this reguard, and both have two.



Edelbrock clearly sttes max of 6 psi and recommends a FPR at 5.5 psi.

Here's a Holley 12-803 FPR I just recently mounted on my old 351M after swapping from a Holley that's seen many years of service for an Edelbrock 1405 600 and finding the truck loading up at idle as the higher psi pumped fuel past the inlet needle in it's seat because the floats cannot apply adequate pressure to keep them shut.

I made an "ell" of some 1"x3/16" steel, welded two tabs to coincide with carb studs, and since I used long studs, mounted the mount attop the nuts holding the carb on and used two more nuts. I mounted the Holley FPR to the "ell". I used a fuel pump pressure tester gage and tee between the FPR and carb to monitor fuel pressure while setting. It started out at 7 psi as I knew it would and cranked down to 5.5 psi and removed the tester and tee.





Pardon the dirty air filter and old looking Moroso Valve Cover .... they'll be replaced soo enough with that 400.