1971 429 cobra jet timing settings

[Stanglover]

I don't seem to have much luck with the search feature, so I'll put this out there as a quick Q&A.

A friend has a 71 429 J code Mustang and can't seem to get it running right. He knows I got my 351 C sorted with the help of my buddies here.

The questions are; what setting does the 429 like? How much initial, how much crank mechanical advance and how much vacuum advance. What is the total mechanical a 429 will tolerate. I think he may have the same basic trouble I had with too much mechanical advance on the crank for the amount of initial he is trying to put in.

 I believe the motor is stock as I know he has not even pulled it from the car.

Any help is most welcome.

Geoff.

 

[Canted 393]

Start at 10 to 12 and go to 35 and see how its runs, then push higher til it pings, depending octane available

 

[TommyK]

That is a high compression engine and it may be challenging to get it to run on pump gas.

 

[Stanglover]

Thanks guys, much appreciated info.

I'll relay that to my friend and as I think he wants me to look at it, it gives me a good start point.

As the 429 and 351 use the same dizzy, I can set up my spare one and see how that works. Right now his is running points, but I'll switch him over to a Pertronix II ( just because I have a spare one)

This is a nice car and will be for sale once he gets it sorted, just to put it out there! (I'd buy it in a heart-beat if I had a bigger garage, but then if I had a bigger garage, the wife would want her car in there!!)

Geoff.

 

[Fabrice]

As Canted said, set to 10-13 deg initial, then I'd really use a vacuum gauge. As you are familiar with 351c, the 351c will tell you in no time he is not happy.

while in my experience, the 429 is less clear, and will sound ok in a broader range. As this beast can consume more fuel than air, its important

you level the carb floats first, then turn idle screw to end. Unscrew 1 1/2 turn and then start engine. once started let it reach temp before do anything.

I would also for idle/2k rpm first disconnect dist vacuum. Once you got it react fine on fast accel from idle/2k, put it back.

If you do it right you should be able do more than 20 miles on a full tank

 

[Stanglover]

As Canted said, set to 10-13 deg initial, then I'd really use a vacuum gauge. As you are familiar with 351c, the 351c will tell you in no time he is not happy.

while in my experience, the 429 is less clear, and will sound ok in a broader range. As this beast can consume more fuel than air, its important

you level the carb floats first, then turn idle screw to end. Unscrew 1 1/2 turn and then start engine. once started let it reach temp before do anything.

I would also for idle/2k rpm first disconnect dist vacuum. Once you got it react fine on fast accel from idle/2k, put it back.

If you do it right you should be able do more than 20 miles on a full tank

 Thanks for your amusing reply and more good info to help out. It's much appreciated for sure.

 These things are gas hogs for sure. I have another buddy with a 429 Torino, he gets about 8 mpg (imperial gallon that is!)