motorcraft 4300 carb info

gmonde · 09-27-2008, 11:19 PM

any one running a motorcraft 4300 carb,looking for some on set up any info would be helpful,tom thanks for you info thanks gmonde

Duane Eiskant II · 09-29-2008, 04:57 PM

i run the 4300D on my combo love it. back to back with dads 780 holley off his 71 runs the same..

Chris1529 · 09-29-2008, 07:39 PM

what CFM is the motorcraft Duane?

Duane Eiskant II · 09-30-2008, 12:24 PM

on the wet flow bench at work its a hole 580

Jeff Lee · 09-30-2008, 06:31 PM

To clarify, the 4300 Autolite is different from the 4300D Autolite in that the D series is a spreadbore with larger throttle blades than the 4300 "non D", correct? I believe the 4300D was rated at about 715CFM. Correct me if you have other info (I run the 4300 non-spreadbore).
And I probably should not reference this as a "spread-bore". Square flange or spread-bore flange may be more accurate.

FED 387 · 09-30-2008, 07:12 PM

According to a buddy of mine these are the specs for both carbs

4300 Carb depending on the particular model these measurements can vary from

441-605 CFM
Venturi 1-1 1/4 in primary

Bore 1 7/16 P--- 1 9/16 S
1 9/16 P-- -1 11/16 S

4300D carb

715 CFM
Venturi 1 1/4 P
Bore 1 9/16 P--2 S

This carb (4300D) is ONLY on 71 Boss 351 Cleveland & 72-74 351 Cleveland engines ---4300D carb will only fit a specific manifold -- Not interchangable with a 4300 manifold WITHOUT an adapter!!!

Comp 387

gmonde · 09-30-2008, 07:40 PM

jeff we do run a spread bore (not much of one ) but it is a square flange bolt pattern
1 9/16 P-- -1 11/16 S and a 605 cfm "man talk about a choke " gmonde

FED 387 · 09-30-2008, 08:05 PM

605 CFM carb came on the 1971 351 cleveland engines NOT the BOSS engines those were 4300D==Comp387

dwydendorf · 09-30-2008, 09:51 PM

The motorcraft and autolite carb with the square (not spreadbore ) baseplate is refered to as the 4300A. As far as I know there were basically two sizes of these carbs, a smaller version that came on the 68 302 and 69 351w engines and the bigger version that came on the 70-71 351c and 68-75 429-460's. I also heard that the AMC's had some of these carbs on their engines. I ran one on my 70 mustang in SS and it is very touchy carb to mess with, a real pain.

FED 387 · 09-30-2008, 10:18 PM

4300 carbs were rated @
441 cfm--67-68 J code engine
470 cfm -69 351W
595 cfm-69 390 S code engine
600 cfm-70 351 W & 351 C engine
605 cfm-71 351 C engine
715 cfm 71 Boss 351 C & 72-74 351 C engines--THIS IS THE 4300D CARB

09-27-2008, 11:19 PM	#1
gmonde Senior Member Join Date: Nov 2007 Posts: 615 Likes: 56 Liked 166 Times in 59 Posts	motorcraft 4300 carb info any one running a motorcraft 4300 carb,looking for some on set up any info would be helpful,tom thanks for you info thanks gmonde

09-29-2008, 04:57 PM	#2
Duane Eiskant II Member Join Date: Dec 2001 Location: Alexandria, Va Posts: 496 Likes: 256 Liked 53 Times in 31 Posts	Re: motorcraft 4300 carb info i run the 4300D on my combo love it. back to back with dads 780 holley off his 71 runs the same.. __________________ Duane Eiskant 1354 Stock/Super Stock

09-29-2008, 07:39 PM	#3
Chris1529 VIP Member Join Date: Dec 2006 Location: West Virginia Posts: 1,367 Likes: 6 Liked 57 Times in 27 Posts	Re: motorcraft 4300 carb info what CFM is the motorcraft Duane? __________________ Chris Bowman The Mountain State Mustang 1984 Mustang GT350

09-30-2008, 12:24 PM	#4
Duane Eiskant II Member Join Date: Dec 2001 Location: Alexandria, Va Posts: 496 Likes: 256 Liked 53 Times in 31 Posts	Re: motorcraft 4300 carb info on the wet flow bench at work its a hole 580 __________________ Duane Eiskant 1354 Stock/Super Stock

09-30-2008, 06:31 PM	#5
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 2 Times in 2 Posts	Re: motorcraft 4300 carb info To clarify, the 4300 Autolite is different from the 4300D Autolite in that the D series is a spreadbore with larger throttle blades than the 4300 "non D", correct? I believe the 4300D was rated at about 715CFM. Correct me if you have other info (I run the 4300 non-spreadbore). And I probably should not reference this as a "spread-bore". Square flange or spread-bore flange may be more accurate. __________________ Jeff Lee 7494 D/S '70 AMX

09-30-2008, 07:12 PM	#6
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,349 Likes: 329 Liked 280 Times in 150 Posts	Re: motorcraft 4300 carb info According to a buddy of mine these are the specs for both carbs 4300 Carb depending on the particular model these measurements can vary from 441-605 CFM Venturi 1-1 1/4 in primary Bore 1 7/16 P--- 1 9/16 S 1 9/16 P-- -1 11/16 S 4300D carb 715 CFM Venturi 1 1/4 P Bore 1 9/16 P--2 S This carb (4300D) is ONLY on 71 Boss 351 Cleveland & 72-74 351 Cleveland engines ---4300D carb will only fit a specific manifold -- Not interchangable with a 4300 manifold WITHOUT an adapter!!! Comp 387

09-30-2008, 07:40 PM	#7
gmonde Senior Member Join Date: Nov 2007 Posts: 615 Likes: 56 Liked 166 Times in 59 Posts	Re: motorcraft 4300 carb info jeff we do run a spread bore (not much of one ) but it is a square flange bolt pattern 1 9/16 P-- -1 11/16 S and a 605 cfm "man talk about a choke " gmonde

09-30-2008, 08:05 PM	#8
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,349 Likes: 329 Liked 280 Times in 150 Posts	Re: motorcraft 4300 carb info 605 CFM carb came on the 1971 351 cleveland engines NOT the BOSS engines those were 4300D==Comp387

09-30-2008, 09:51 PM	#9
dwydendorf Member Join Date: Jul 2006 Location: michigan Posts: 162 Likes: 250 Liked 19 Times in 7 Posts	Re: motorcraft 4300 carb info The motorcraft and autolite carb with the square (not spreadbore ) baseplate is refered to as the 4300A. As far as I know there were basically two sizes of these carbs, a smaller version that came on the 68 302 and 69 351w engines and the bigger version that came on the 70-71 351c and 68-75 429-460's. I also heard that the AMC's had some of these carbs on their engines. I ran one on my 70 mustang in SS and it is very touchy carb to mess with, a real pain.

09-30-2008, 10:18 PM	#10
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,349 Likes: 329 Liked 280 Times in 150 Posts	Re: motorcraft 4300 carb info 4300 carbs were rated @ 441 cfm--67-68 J code engine 470 cfm -69 351W 595 cfm-69 390 S code engine 600 cfm-70 351 W & 351 C engine 605 cfm-71 351 C engine 715 cfm 71 Boss 351 C & 72-74 351 C engines--THIS IS THE 4300D CARB