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Discussion Starter #1
Ok, this is where I am at.
New plugs, wires, Dis cap & rotor. there are no points MSD ignition. lots of spark. I am running about 9lbs of vac Steady, and hear a miss the timimg is good.
here is some back ground. Put a 625cfm Road Demon on 351C 2V, Performer intake. Saturday got all the work done with the intake, carb tuned in, went for a ride, Ran "GREAT" for about 20 min, with 16lbs of Vacuum during the ride I could hear a miss and not run good, got home put the Vac gauge on it 9lbs vac, Ok Monday took intake back off, maybe has a leak. Put new intake gasgets on VERY Carfully make sure every thing is sealed good. Stll know good, over the week I have replaced everything stated above. What could it be, Any Ideas???????? I'm starting to think it isn't anything easy anymore :(

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73 351C C6 3.25 T-lock
Jesus is all the world to me!
Mustang's are just a Hobby
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Do a compresion test.

my first guess of blown head gasket. and one cylinder is blowing his compresion into his next door neighbor and visa versa.

My second guess is a vacume leak. When nothing else works i fill the engine up with smoke and see where the smoke comes out. Glad to give details if interested.

Third guess is the timing chain skipped a tooth.
 

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Discussion Starter #3
I wonder if it is between the #7 and #8 chambers????
if I pull the plugs on either one there isn't a huge difference in how the car runs, like when I pull any other plug wire.
I think it is time to get a compression tester!!!!!!!

http://albums.photopoint.com/j/View?u=1603896&a=12227373&p=44503083.jpg
73 351C C6 3.25 T-lock
Jesus is all the world to me!
Mustang's are just a Hobby
http://www.folksite.com/TFOB
 
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I'm not an engine guru, but I read a test you can do is with the engine in idle, diengage 1 plugwire and listen for a change in the motor. reconnect and move to the next one. the theory being if all cylinders are hitting right...a noticeable change will occur when you do this.
I would also.. (don't be insulted) do the easy step #1 of making sure all the wires are in the right firing order in the distributor. But as I stated. I am not a guru. but knowing which cylinder is missing may help. Also check the plugs for fouling. As they are New plaugs.. a foul plug will point out the culprit too.

1968 Coupe, 6cyl Std, Bench Seat. Driven through 10 years of College.
 
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I'm sure you know but I got a doofus award for this one, rememer the cleveland has a different firing order than the other small blocks 13726548. I had the same symptoms that you have.
 

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Discussion Starter #6
Right firing order, Is looking more and more like a blown head gasket.
will know more today after test

http://albums.photopoint.com/j/View?u=1603896&a=12227373&p=44503083.jpg
73 351C C6 3.25 T-lock
Jesus is all the world to me!
Mustang's are just a Hobby
http://www.folksite.com/TFOB
 
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