• Mustang Forums
  • 1965 - 1973 Classic Mustangs -General/Talk-

351 Cleveland Missing At 2300rpm

  • Thread starter Thread starter Dommie C
  • Start date Start date Dec 21, 2015
D

Dommie C

New Member
Dec 21, 2015
4
0
1
Dec 21, 2015
#1
  • Dec 21, 2015
  • #1
351 Cleveland missing at 2300rpm-need HELP!!!
I have 73 351 cleveland-rebuilt crate engine.
edelbrock AVS 650 carb
MSD Distributor
Engine has developed a miss/backfire at 2300rpm.
Not sure if fuel or spark or internal engine issue. Any assistance would be greatly appreciated.
 

tos

Founding Member
Apr 27, 2001
896
68
59
Cincinnati Ohio
Dec 22, 2015
#2
  • Dec 22, 2015
  • #2
Exhaust or carb backfire? I'd start off by pulling the plugs to see what they look like. Could be timing, flooding, plug fouling, sticking valve? How does it run otherwise? Idle?
 

LILCBRA

I wish I didn't have all of these balls in the air
Mod Dude
Dec 6, 2005
6,380
5,364
194
Corn County USA
Dec 23, 2015
#3
  • Dec 23, 2015
  • #3
+1 for tos's post

We don't have a lot to go from like how old is the rebuild, what ignition system do you run, engine specifics, etc. Bad gas, worn spark plugs, bad plug wires, vacuum leak, fuel delivery issue (i.e. leaky carb on one side or not enough fuel from a partially clogged filter, etc), ignition system issue (i.e. bad ground or bad signal), timing not advancing properly and so on and so forth. Could be one or many things depending on several factors.
 
D

Dommie C

New Member
Dec 21, 2015
4
0
1
Dec 27, 2015
#4
  • Dec 27, 2015
  • #4
Dommie C said:
351 Cleveland missing at 2300rpm-need HELP!!!
I have 73 351 cleveland-rebuilt crate engine.
edelbrock AVS 650 carb
MSD Distributor
Engine has developed a miss/backfire at 2300rpm.
Not sure if fuel or spark or internal engine issue. Any assistance would be greatly appreciated.
Click to expand...
tos said:
Exhaust or carb backfire? I'd start off by pulling the plugs to see what they look like. Could be timing, flooding, plug fouling, sticking valve? How does it run otherwise? Idle?
Click to expand...
exhaust backfire-pulled plugs and they are black as coal. Replaced plugs and ordered calibration kit for carb. I'm 99% sure this is problem, but I'm sure what/or how lean to go?? I'm trying to make sense out of the edelbrock calibration chart
 
D

Dommie C

New Member
Dec 21, 2015
4
0
1
Dec 27, 2015
#5
  • Dec 27, 2015
  • #5
Dommie C said:
exhaust backfire-pulled plugs and they are black as coal. Replaced plugs and ordered calibration kit for carb. I'm 99% sure this is problem, but I'm sure what/or how lean to go?? I'm trying to make sense out of the edelbrock calibration chart
Click to expand...
Idles great-just replaced intake manifold gasket due to vacuum leaks. Rebuild only has about 1500 miles on it. At one it was popping through the carb, which we attributed to lean condition being caused by vac leak? Now vac leak is gone, engine is running super rich and backfiring at 2300 rpm. timing is at 10. MSD distributor with vac advance using the pertronix 3 coil.
 
D

Dommie C

New Member
Dec 21, 2015
4
0
1
Jan 2, 2016
#6
  • Jan 2, 2016
  • #6
Dommie C said:
Idles great-just replaced intake manifold gasket due to vacuum leaks. Rebuild only has about 1500 miles on it. At one it was popping through the carb, which we attributed to lean condition being caused by vac leak? Now vac leak is gone, engine is running super rich and backfiring at 2300 rpm. timing is at 10. MSD distributor with vac advance using the pertronix 3 coil.
Click to expand...
Changed metering rods in carb with no result. Is it possible springs need to be swapped in MSD distributor?
 

tos

Founding Member
Apr 27, 2001
896
68
59
Cincinnati Ohio
Jan 7, 2016
#7
  • Jan 7, 2016
  • #7
I had a similar problem (running rich and black plugs) I adjusted my mixture needles and installed a Pertronix second strike ignition and now it runs great with no carbon fouling. This second strike is adjustable in 2 deg increments so you can tune it to throw that second spark however works best for you. it also has a built in adjustable rev limiter. I love it.
 
You must log in or register to reply here.

Similar threads

M
1973 Mach 1 missing engine and transmission, help!
  • MI6Agent007
  • Jun 30, 2024
  • 1965 - 1973 Classic Mustangs -General/Talk-
Replies
13
Views
2K
1965 - 1973 Classic Mustangs -General/Talk- Jul 14, 2024
Mcmahst
Resolved Need help!! 289 with 351 firing order issues
  • Falcon67
  • Jun 13, 2024
  • 1965 - 1973 Classic Mustangs -General/Talk-
Replies
7
Views
2K
1965 - 1973 Classic Mustangs -General/Talk- Jul 6, 2024
2Blue2
M
Engine Unexplainable Exhaust Pop and Gurgle
  • Mrnissen122
  • Feb 14, 2026
  • Fox 5.0 Mustang Tech
Replies
12
Views
574
Fox 5.0 Mustang Tech Feb 18, 2026
Noobz347
9
Forced Induction Prepping for supercharger on non-stock build
  • 91fox427
  • Nov 25, 2025
  • Fox 5.0 Mustang Tech
Replies
7
Views
415
Fox 5.0 Mustang Tech Jan 5, 2026
Qtrhrse23
Q
6
Hey all,I’m putting together a 302 for my 1968 Mustang and wanted to post the combo + some questions to make sure I’m not missing crucial
  • 68_Disgustang
  • Feb 22, 2026
  • 1965 - 1973 Classic Mustangs -General/Talk-
Replies
4
Views
896
1965 - 1973 Classic Mustangs -General/Talk- Jun 20, 2026
gray owl
G
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1965 - 1973 Classic Mustangs -General/Talk-
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?