Plugs foul / gas in exaust

[talentfreak]

I have a 350 small block pretty much stock except for a larger cam .510 lift, 275 heads that have not been ported or polished, double springs, and high performance lifters that came with the Blue Racer Cam and I am using a edelbrock 750 carb, edelbrock intake.
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The cam has a .510 lift. I also have a MSD Ignition kit installed. And the fuel pressure is only at 4psi with a quadra jet carb, it isn't the carb., because the quadra jet carb., is in replacement to the Eld. 750 that is brand new I just took it off to see if it was the problem, still too much fuel is going to the plugs and out the exaust, the #2 and #3 plug seem to foul first the heads are stock 275 and so is the motor it is a 350 4 bolt main, I don't know what to do with it? One suggestion I was given was the vaccume line to the booster, that the booster may have a leak? How do I check for the leak? It was bought as a used part so I could put Disc Brakes on the car!


Any help will be appreciated!

 

[dq409]

If the booster was leaking it would run lean. You say stock 350 with a fairly large cam and stock heads with a 750 carb?
My guess,,,,, too much cam and carb.
What is the compression and other cam specs? Like duration @ .050 and centerline?,,,dq

 

[talentfreak]

Haven't checked the Compression yet, we were a little too tired after working on it all day Sunday, hopefully this weekend we are going to check it. What should it be? I am a little new to the mechanical, as you can see from the photo I am more paint and body.

 

[dq409]

The most a compression check will do is tell you the condition of the rings and valves. It will not tell you what the compression ratio of you head and piston combo is.
Can you go to the old owner or any one you know (machinist) that has knowledge of what the engine has inside of it?
What about the other info I asked about. It is important to have this info for refference to trouble shooting.
It`s OK not to know about machanics because you`ll learn very quickly and the stuff you get stuck on you will find the answers here or other places!!
Welcome,,,,dq

 

[dq409]

I see you change photos and have the cam card.
Well my guess is too much cam unless your running 10.5 - 12 to one on your compression.
This would be a great bracket racing cam. You will need a high stall coverter if it`s an auto with a cruse rpm of 4200-4600. Big on the high RPM but won`t have much in the low rpm range.
What are your plans for this car??,,,dq?

 

[Fathead Racing]

Carb loading up.

As with most Rochester carbs the quadrajet has a power valve that enriches the the fuel under low vacuum conditions. With that big of a cam my guess is that your engine has low vacuum at idle. With low vacuume at idle the carb enrichment system thinks that the engine is seeing a load and is trying to compensate by pouring fuel into the system.

 

[talentfreak]

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I am just going to drive it for fun not race, the cam was recomended by my brother in lay who really likes to race, maybe we just have too much cam. It sounds like the problem.

 

[talentfreak]

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The forums are great, I don't think I could have done half the car with out them, thanks alot.

 

[talentfreak]

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I remember now why he was wanting to put that size cam, he mainly was wanting the sound of the cam, I have a 2.5 inch flowmaster exaust system running from the hooker headers.

 

[dq409]

Ohhh, Yes the power valve !!! But I still think you have too much cam. Yes the sound is fun ,,,but trying to drive a car that way isn`t ! You can get the Rappity -pappity with smallers cams matched to your other componites and enjoy driving it.
O WELL you can always say we told you so !! Heeee heee
Have fun with it and and once it`s on the street you can make the changes nessisary,,,dq

 

[Fathead Racing]

Big cam

You can still run that cam, BUT, now you will have to build the car around the cam not the other way around. High ratio gears, 3500 stall converter, power valve adjustment etc. Small blocks love to scream!

 

[dq409]

Pdr,,,If the engine has low comperssion ,,,less then 10.5 it will run like a dog,,,,dq

 

[Fathead Racing]

Comp

That would be the ETC.

 

[talentfreak]

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Well I am going with a smaller cam, new lifters and springs, I am going to start tearing down this weekend. Thanks for all your help, I am sure you will be hearing from me again soon.

 

[dq409]

Talent,,,,Stick around and join in the fun.... Try and figure out your compression ,,rear gears and pick a cam that will match how you intend to use it. you can get a faily lopy sounding cam that will be good on the street. call Crane cams and talk to one of their tech guys. they seem to be one of the best I`ve talked to as far as willing to help. ,,,You`ll have a Great Looking and Running car ,,,Good luck,, dq

 

[talentfreak]

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The rear gears are Strange 373 with an Eaton Posi Unit. 4spd trans, hurst inline shifter.