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Questions on 351C Performance

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Reggie:
I have a 351 Cleveland 4bbl 1973 Ford Mustang.  The car starts OK but it doesn't have very good performance. The engine hesitates slightly when I agressively step on the gas.  I see a bit of black smoke when I start during warm up, and I think it is running a bit rich.  I changed the plugs, plug wires, rotor, cap and replaced the points with a magnet system.  This really improved the car's performance as it was hesitating real bad before I did this.  I set the timing at 6 degrees before TDC.   I've been told that I now need to rebuild the carb if I am still having problems.  I was thinking about buying an Edelbrock 650 but was wondering if anyone could give me some tips on whether this is a good idea.  I was also looking at a Carter AVS 650 CFM (rebuilt) as it is much cheaper.  Claims are that it is the same as an Edelbrock 650 CFM.  The car has not been modified other than going from a 2bbl to a 4bbl and dual exhaust, but no headers.  

Do you think a carb change will help improve my performance?  Any other recommendations?  I was thinking about also replacing the intake manifold, and would welcome any recommendations.  The car starts good and is reliable.  It runs very smooth but idles a little rough.  If you never stepped hard on the accelerator, you probably wouldn't think there is a problem.  Carb and manifold look like stock Ford equipment.

racedraper:
defently get the edelbrock card. all adjustments are exturnal. but carter will be fine also. I would also get the Ignitor. Its a direct replacement for points and condincer,this makes its electronic with out all the wires al fit under the distributor cap and only cost 75 bucks. Headers will also help. making it breath is what it needs. Also what is your gear ratio. if it is anything like my 73 its a 2:72 very high gear, out a 3:73 and watch you head snap back.. replace the air filter with a nice K&N it helps with air delivery plus it reusable. Does your car still burn LEADED gas or has the Valve seats been changes out?

what is your spark plug gap? even though they sell pre gapped plugs they are never the same. this will also cause small preformance problems.. with everything I sudjested it should cause about 1000.00 bucks total unless you shop Ebay and get great deals. But I would first get the Ignitor Box for sure

Reggie:
I tried the Ignitor and it seems to work well.  No adjustments, seems pretty solid.

I think the ratio is 2:72 as this was the original ratio and I don't think that there was any change to the differential.  I will see what it takes to change to 3:73.

I found a rebuilt Carter 650 CFM on Ebay for $175.  I was cautioned about buying a rebuilt, but a new 650 CFM Edelbrock is $330.

I replaced all plugs and gapped everything to 36.  The plugs I removed looked like they were gapped to 45.  The timing spec for a 2V is 6 before TDC, but for a 4V it is 16 before TDC.  I am using 6, but I may try 16 and see how it runs.

I've been running 93 unleaded in the car but I don't know if the valve seats have been modified.

Sounds like I would be better off buying a set of headers before changing out the intake manifold?

racedraper:
call PAW If  I remember I bought a new edelbrock 600 cfm carb and preformer manifold for 400 bucks as a combo package. you can also upgrade the distributor ,and that a cleveland a 429/460 is the same.

Im with you I never have change the rear end . And yes 2:72 is stock gearing .It was the attempt to help with fuel economy lets see you stang post a pic

Reggie:
Not sure if I posted the picture right.

The car is in pretty good shape.

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