# Better engine performance?



## xconcepts (Jan 4, 2009)

So I've either had a head gasket blow or some other gasket start leaking pretty bad. I won't be able to drive her again until I get back from Afgan in Aug, so I'm going to just have the whole engine pulled and rebuilt. Going to do alot by myself and a few friends that know there stuff and have a cherrypicker. 

So my question is there anything I can do to get a little more power without changing anything? Boring the cylinders? Anything else that wouldn't change it without devaluing it? 

I was told a slightly different cam has been in it since it was last rebuilt. It hasn't been rebuilt since 78/79 so its probably due anyways.


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## dimitri (Feb 13, 2009)

Where was it leaking? Coolant or oil? Our engines always run hot. The more you bore our engines the hotter they get. Only bore if it is abosolutely neccessary. Why do you think you have a blown head gasket? You can buy a from Napa that test the coolant for hydrocarbons. Do a dry and wet compression test. I would not pull the engine if the bottom end is strong. If you have a bad head gasket pull the heads and get a book on porting and port your heads and intake. You can also fill your crossover with aluminum.


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## xconcepts (Jan 4, 2009)

Its oil, I've seen it.

I replaced the breather filter on the valve cover and after driving about 15 miles home was smoking bad from the engine bay. I had oil all down the passenger side of the engine and was smoking bad. I thought it was the rear main seal since I saw oil dripping from the flywheel. But today when I was getting the mixture on thr tripower corrected I saw a good amount of oil reight below the spark plugs. 

And what do you mean by fill the crossover with alluminum?


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## dimitri (Feb 13, 2009)

The exhaust crossover on the heads in the middle where exhaust gases preheat your fuel. I melted some aluminum and poured it in the head. Do you have a vacuum gauge? Do you have a compression gauge?


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## freethinker (Nov 14, 2009)

xconcepts said:


> Its oil, I've seen it.
> 
> And what do you mean by fill the crossover with alluminum?




its not a good idea on a street car. your choke will not work if you do it. it will not make a noticable difference on a street car.
as i have said many times on this site. if you want a seat of the pants feel in the cheapest possible way without doing something that will hurt originality a mild nos system is something to think about.


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## dimitri (Feb 13, 2009)

On my 68 400, stock heads, intake and carb I have run it that way for 250,000 miles and my original stock choke works great. It makes a huge difference in horse power. That's why all of the aftermarket intakes don't have an exhaust cross over. And it is real easy to put it back to stock if you want.


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## freethinker (Nov 14, 2009)

dimitri said:


> On my 68 400, stock heads, intake and carb I have run it that way for 250,000 miles and my original stock choke works great. It makes a huge difference in horse power. That's why all of the aftermarket intakes don't have an exhaust cross over. And it is real easy to put it back to stock if you want.


oh really. exactly how does the choke spring heat up with the crossover plugged?
huge increase in power? i must have done it wrong on the dozens of pontiacs i have thrashed on the streets since 1970 because i have never noticed much difference. it alway was the cool thing to do though.


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## dimitri (Feb 13, 2009)

180 degrees is plenty of heat for the choke coil to expand and operate. It does not need 1000 degrees. In 1979 I bought a book; Pontiac High performance Engine Design and Blueprint Assembly by Craig Hendrickson & Kern Osterstock of H. O. Racing Specialties, Inc. They know their stuff. In the book there is a section for street application. This is something they suggested. Kauffman racing equipent is also for filling the cross over.


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## xconcepts (Jan 4, 2009)

I dont have ant gauges. A friend does thou, but I am leaving in about 3 weeks so no point until I get back


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## dimitri (Feb 13, 2009)

Take care, we'll talk when we get back. If you get the chance change the engine oil and filter before you go.


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## geeteeohguy (Feb 2, 2008)

X, be safe over there, and when you get back, we'll be here to help. Never mind the aluminum in the intake right now. It sounds like you have an oil leak. Could be something as simple as a valvecover. Or, it could be blowby past the rings signalling a worn engine. If you're not losing coolant, and if your dipstick isn't milky, you don't have a blown head gasket. Dimitri is right....overbore is not the answer unless you're out of spec. Thick cylinder walls are your friend...they don't overheat, and they don't flex under high load. A 389 can be made to run very very strong with a set of dished pistons, good cylinder heads, appropriate camshaft, and free-flowing exhaust. The basics, done right, will "get r done". If you DO have coolant in the engine oil, drain the coolant and the oil before you deploy and remove the spark plugs so you can squirt oil into the cylinders. It would be a real drag to get back in a fefw months to a rusted solid motor, now junk. Don't leave it with coolant/water in the cylinders!!! Good luck.


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## xconcepts (Jan 4, 2009)

Eh, wife will be here to start her every week, just won't be driven much. I know its an oil leak somewhere, its alot too. But there is no coolent in the leak. I just know that the leak is below the sparkplugs and isn't the rear main like i thought. I get alot of oil getting burned and smoking up the passenger side of the engine bay.


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## geeteeohguy (Feb 2, 2008)

Sounds like the oil filter, filter housing or oil pressure switch...could also be the PCV valve grommet at the right rear (pass side) of the valley pan.....If it's that big a leak, you can find it!!


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## Indecision (Oct 24, 2010)

freethinker said:


> its not a good idea on a street car. your choke will not work if you do it. it will not make a noticable difference on a street car.
> as i have said many times on this site. if you want a seat of the pants feel in the cheapest possible way without doing something that will hurt originality a mild *nos* system is something to think about.


This isn't The Fast and The Furious, it's called nitrous. That being said I would recommend Zex over NOS with an FJO nitrous controller. It's digital, which I know a lot of you old school guys hate, but it has a window switch and WOT switch. It's the safest and most effective way to run nitrous that I know.

To the OP, be safe in Afghanistan, I did 2 tours there, the last one was cut a few months short unfortunately. I am alive though, take care of yourself out there.


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## 66tempestGT (Nov 28, 2009)

if the leak started when you replaced the breather it sounds like you are building up crankcase pressure. maybe put the old one back on. it could have pushed out a gasket or maybe just found a small existing leak and is forcing more oil through it. it sounds like you didnt have this problem before the breather change, its the first place i would check.


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## xconcepts (Jan 4, 2009)

So what breather do you all use?


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## dimitri (Feb 13, 2009)

Nothing beats the factory set up!!!!


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## xconcepts (Jan 4, 2009)

So where can I get an original breather? Yearone only has push in and mine is a twist in.


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