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Ok I still have the problem of poping in the tail pipe. I have put in new carb, distributer, coil, plugs, wires, cap, rotor, petronix ign. with no change. Yesterday I tried a compresion test that may have put me on the right track. I got a reading of about 150 on all cylanders except for the #6 wich came up about 115-120? Is this a head problem or a piston ring problem? It doesnt burn any oil and I dont see any coolent in the oil. And here is the next big question. When I got the car I was told the motor is a 351W, Wich seemd to be right since the firing order was a 351, the intake manifold is an edlebrock 351W, and the coolant intake is on the manifold.....But the plugs are 14mm threads not 18mm like all the documentation I have read states it should have???? Could this be a Winsor with 302 heads??? or a 302 with winsor cam and intake??? Is it worth pulling the motor and trying to rebuild it without knowing what it realy is? Or does anyone have a good 351W/C or 302 for sale?
 

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Sounds like a burnt valve to me, that will cause the popping sound. Your engine is a 351 if thats what it says on the intake manifold because the manifold doesn't interchange with other motors, not even a 302, Most likely you either have a newer 351 or the heads have been replaced with newer ones. The cheap way-do a valve job. the performace way-aftermarket heads I'm not sure of the ratios but a newer 351w would have lower compression than the stock one due to dish pistons.
 

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i had a dead stock 351W 2bbl in my car when i got it. most has been changed on it except for the heads and cam. the engine puts about 175 to 180 psi on a compression test. thats abour right with 9.5 compression ratio right?? somehow i doubt that the previous owner put in flat tops in the cars old life. but anyway, your 351 sounds like a burnt valve definatly. not too big a deal,, so have fun.
 

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If you have your exhaust going straight back to the rear without an H pipe, X pipe or crossover you will get a popping sound out of the tail pipe. There is no relief of pressure when the exhaust is straight back to the rear of the car. A cheap way to see if this is the problem is to have a pipe welded between the dual exhaust to releive some of the pressure that is built up. Just my 2 cents.:)
 

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351 W

I have a 351 windsor still in a 70 cougar for sale. I've had the heads done it can now use unleaded I also live in Mich in Detroit if interested make offer. You would have to pull it out of the car yourself.
 
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