1972 351 Cj 4v - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

72torino · 01-23-2005, 19:05

Hey people!

I'm Darryl from BC Canada, I'm new to this forum.

I have a 1972 Gran Torino with a 351C-4V (CJ Code Q). It recently got rebuilt last year (2004) and I have a problem.

It is harshly over-carbuerating with its new Edelbrock Performer 750cfm 4bbl. Is there any way to detune this carb ?!

My 72 isn't stock. dual 2.5" exhaust (h-pipe + flowmasters), bored over, 3000rpm stall, 3.55 gears, posi, ram air, edelbrock perf. intake, rebuilt for longevity and strength.

Should I put the old 625 carter 4bbl back on ?! Reason why it has a 750cfm cause the engine shop dude (NEVER going back there again --- long story) has a "bigger is better" mentality.

Thanks in advance guys/gals!

Work Horse · 01-23-2005, 19:43

Gidday Darryl, and welcome to the forum.

No you cannot detune the 750cfm, you need a smaller carb. I have a mild 351 which has run well with a 600cfm and 650cfm.

Your 625 carter sounds the correct size, but i'm not sure it will bolt up to the performer you would need to check.

That's a great looking Torino!!!

xyfmtjoe · 01-23-2005, 19:45

heya Darryl,
welcome mate. no i doubt that its over carbed at! they are an excelent carb when tuned rite. My cousin used one 2 great effect on his fairly warm 2V 351 he built a couple of years ago but they can be a pain to setup correctly. You can get performance tuning kits for them im sure of it

What size shaft are you using. to give you an idea im running a 780vs holley on the same manifold as you with 224@50 and 502lift on both int/exh with 2V's in my early falcon ute and it runs great.

BTW awesome ride
Joe

Falcon67 · 01-23-2005, 19:51

Those are pretty good carbs - what exatcly makes you think it's too big? A 750 vacuum secondary on a mild 4V is not very big at all. What's it doing (or not doing) and maybe we can puzzle it out.

72torino · 01-23-2005, 21:55

Thanks for the warm welcome guys!!

My symptom for this carb (and why I think its over-carbed) is when it starts , it starts up fine, then a few seconds later it bogs down automatically and when I keep the gas pedal on to keep it from stalling, it blows a lot of crap outta the exhaust.

Then I check the oil to see how much fuel is in the oil pan and it honestly smells like its 100% fuel.

Could the choke play a part into this ?!?!

xyfmtjoe: My camshaft specs are this:
Comp Cam
Dual Energy Hydraulic Flat Tappet (2000 - 6000rpm)
Choppy idle - superiour high end power - works with mild converter
Grind # 275DEH
@ 0.50
intake: 219
exhaust: 232

VALVE LIFT
intake: .515
exhaust: .541

Work Horse · 01-23-2005, 23:55

Sorry 72torino, I am confusing the issue with my post. As the other guys have posted a 750cfm on a 351 is common and should run fine. But it sounds like you have some fine tuning to do. I have played a little with Holleys but have on idea with the edelbrock carbs. But some people swear by them.

I have played around with my Van at the strip a lot, 2V P&P heads 214/224@50 510/536Lift 112Lobe sep, performer manifold 2100rpm stall 3.32:1 lsd 3750lbs.Ran:
14.3@95 750Vacsec
13.9@97 600Vacsec
13.4@101 650Dp
So as you say bigger is not always better

72torino · 01-24-2005, 11:00

Quote:

Originally Posted by Work Horse

S

I have played around with my Van at the strip a lot, 2V P&P heads 214/224@50 510/536Lift 112Lobe sep, performer manifold 2100rpm stall 3.32:1 lsd 3750lbs.Ran:
14.3@95 750Vacsec
13.9@97 600Vacsec
13.4@101 650Dp
So as you say bigger is not always better

Wouldn't it have something to do with compressing more air through smaller ports? (625 vs 750) thus increasing air pressure?

I don't know.... I have the physics on the tip of my toungue, its just not coming out lol.

superbird302 · 01-25-2005, 05:24

my 351c with 750cfm holley in my XA coupe was doing that recently. its got a big electric fuel pump, and somehow the fuel pressure had increased from 7psi at idle to 21psi. as a result it would start, idle for a few seconds then stall just like yours. basically it was choking with too much fuel at idle.

i would put a fuel pressure gauge on it to check the psi. very easy to adjust the PSI with the regulator.

by the way awesome torino

xyfmtjoe · 01-25-2005, 06:49

hey darryl,
tha cam should be good for your bus and cant help but agree with superbird. are you running an electric pump or mech? that combo should go great when sorted properly.
Joe

ebxr8240 · 01-25-2005, 08:45

Carb size is o/k its the tuning and jetting that needs sorting out..
Sounds like your float level is too high, adjust float and check fuel presure??
Is this a brand new carb ? Power valve, needle and set o/k...
What are the jet sizes etc...Fuel smell in oil is classic over rich condition..It could be perculating and flooding when engine is turned off also????