351C performance question - Please chime in

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bsbeck
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351C performance question - Please chime in

#1

Post by bsbeck » 03 Oct 2018, 16:05

My M code 351 Cleveland with 4V has now had the carb rebuilt, the timing set, electronic ignition with matching coil and new plugs. It's still quite boggy on take off. I mean barely able to turn the wheel over. Now once it gets up to about 60 mph, it's pulling like a son of a gun. It's got an FMX auto and a special order 3.00 axle ratio.

I've still got a vacuum leak in the power brake booster and those parts will be here this weekend. We set the timing at 10 degrees. Is it the rear axle ratio and the vacuum leak that's killing the performance???????????
Scott B.

1970 Cougar Eliminator (Competition Blue / Black Comfortweave)
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canted 393
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Location: New Hampton IA

Re: 351C performance question - Please chime in

#2

Post by canted 393 » 03 Oct 2018, 16:53

Set your timing to 12 then see if it knocks during acceleration if not try 14. Make sure your advance is working properly.
I have a twin to your car and it chirps the tires no problem. Maybe unhook your brake booster first and plug that port before anything else, 1 change at a time.

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bsbeck
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Re: 351C performance question - Please chime in

#3

Post by bsbeck » 03 Oct 2018, 19:47

Canted 393, I checked and advance is working properly. What you said is my next steps. Gonna change out the power brake booster and master cylinder and then start raising the timing till it pings then back it off a tad. Do you think the 3.00 axle plays into the boggy performance???
Scott B.

1970 Cougar Eliminator (Competition Blue / Black Comfortweave)
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bsbeck
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Re: 351C performance question - Please chime in

#4

Post by bsbeck » 03 Oct 2018, 19:48

Canted 393, I want to see pics of your car. Michael confirmed there are 8 cars registered configured the same as mine. I want to know who all those 8 are.
Scott B.

1970 Cougar Eliminator (Competition Blue / Black Comfortweave)
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cj750
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Location: Siloam Springs, Arkansas

Re: 351C performance question - Please chime in

#5

Post by cj750 » 03 Oct 2018, 23:24

Lower gears would help, but it should still run a lot harder than you describe with the 3.00:1s.
Fixing vacuum leak(s) should be first priority.
Are you disconnecting the vacuum advance when you check the timing?
What carb does it have?
What cam?
Every post I make comes with a request for corrections. I'm here to learn.

1969 Cougar Eliminator 351 4V, yellow
1970 Cougar Eliminator 428SCJ, black

canted 393
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Location: New Hampton IA

Re: 351C performance question - Please chime in

#6

Post by canted 393 » 04 Oct 2018, 05:45


Mine is a 351c with a/c and white interior.
Having more gear never hurts with 351c but a 3.00 gear isn't terrible, how tall are your tires mine are 26".

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bsbeck
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Re: 351C performance question - Please chime in

#7

Post by bsbeck » 04 Oct 2018, 16:07

Yes vacuum advance was disconnected when checking the timing. I'll check the tire size and report tonight. Carb is an Edelbrock 1407 which is 750 cfm and freshly rebuilt. I have no clue what cam is in it. I've only had the car for 2 months now.
Scott B.

1970 Cougar Eliminator (Competition Blue / Black Comfortweave)
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bsbeck
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Re: 351C performance question - Please chime in

#8

Post by bsbeck » 04 Oct 2018, 16:08

Canted 393, thanks for the pic of your car. Beautiful. I will be going back with the Cougar styled steel wheels on mine.
Scott B.

1970 Cougar Eliminator (Competition Blue / Black Comfortweave)
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bsbeck
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Re: 351C performance question - Please chime in

#9

Post by bsbeck » 05 Oct 2018, 13:24

Still looking for people thoughts????
Scott B.

1970 Cougar Eliminator (Competition Blue / Black Comfortweave)
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Mrcj001
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Re: 351C performance question - Please chime in

#10

Post by Mrcj001 » 09 Oct 2018, 18:56

The vacuum advance is adjustable. Disconnect the hose from the advance assembly and insert a Allen wrench inside it. I think it's a 3/32 but not sure. Turn it it counterclockwise a turn or two and see if that helps. I chased a bogg for months and this fixed it.
1970 XR-7 351C non/AC

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