So, long story short, my RH head gasket is toast. The car runs beautiful, but my plaguing oil leak is indeed the back of the RH head. After spending $300 to have the intake gasket replaced (added an Edelbrock TBI intake at that point), I'm mad for having done that work when the head gasket needed to be done as well, as both were leaking in the end...oh well...

Anyway, to have the dealership I work at (don't get me started on "stealerships"...I know these guys, they do good work, they won't screw me like the last guy did, and if anything goes wrong they've got my back...$48 an hour isn't too awful either) replace both head gaskets while they're in there will cost me a little under $1,000, including replacing the valve seals and cleaning everything up.

Or, crate 350s start around $1,400 at Scoggin Dickey, so herein lies the issue

I'm not sure how much labor they'll charge for the swap, but the service manager said it'd be the same or less than the same to do the head gaskets on my 114k mile motor. So, my question is this...I don't have the time or expertise for my own tune, as I work 60 hours a week and don't really do much beyond basic tune up stuff. What crate engine should I look at? Just a regular replacement 350 long block meant for a truck? I've read the 305 to 350 swap thread, and other than a tbichips.com chip and a few parts from Auto Zone, I appear to be all there...

My main question is, without tuning, I assume I can't go very radical with my crate engine choice? Should I just throw some Vortec heads on the 305 while I'm in there instead? My Edelbrock intake will not work in that case, correct? The engine runs beautiful, but with 114k on it, I'm wondering how smart it is to spend that kind of money on this engine. I don't need too radical...I know a stock 350 TBI in a truck was 210hp. With my full exhaust (I will add Edelbrock TES system when its out of the car) I already have, open element, intake and an ok aftermarket chip, I imagine I can get it up to around 235-240hp...which is stock 350 TPI territory, which is fine for me...

Again, this needs to be inexpensive so the fiance doesn't get pissed, and easy enough that I can give the parts to a respectable tech and say " do it," and it gets done. Any help is really appreciated...

 

Are you sure that isn't a valve cover gasket?

 

I wish it was that easy...I already replaced those back in February, thinking that was the issue because the RH one was leaking so bad. I later saw that it wasn't

 

The head gasket wont result in an oil leak. All the oil passages are in the block itself. Most likely the head gasket would blow out, maybe into a coolant passage, causing the car to run bad and/or belch steam that smells like coolant. If its not doing either of these things, then I wouldnt sweat it. If your not tuning, leave the engine as is, and upgrade the exhaust to a full 3" system and get better gears. That will do a good deal to increase the fun factor. Throw in tuning, and you could even net another 20-30 HP.

In stock form, the goodwrench crate 350s are pigs. The shortblock is ok for a build up if you dont mind a lower CR due to the dished pistons, but in stock form they will only be marginally more powerful then your current L03.

 

Well, the engine is leaking pretty significantly from behind the RH head, leaving spots on the ground, coating the underside of the car, and even leaving specs of oil all over the back bumper up on the highway from oil blowing out the back!! I need to fix it...its simply making a mess...

When you're under it, you can see that the metal gasket is pushing out of the back of the head, and that is where the leak is originating from. We degreased all underneath it, and let it run on a lift for almost 2 hours at idle...the only place oil reappeared was from the back of the head, running down...

It has to be a blown head gasket...what else could it be? I mean, the car is indeed still fully driveable...its leaked about 2 quarts in around 3,000 miles. The engine runs beautiful, which is why I almost feel like its a shame to pull a perfectly running engine. But the leak is making a mess of my driveway, my garage floor and the underside of the car itself...not to mention, when you get off the highway with it after a longer drive, it smells bad when you come to a light because of all the oil running down the block and onto the exhaust.

I have to do something, its just a matter of what. I talked to a guy last night I met awhile back who works at a shop and does work out of his house on the side, and has apparently done a ton of motor swaps on third gens. My thoughts at this point are to just spend the $$$ and fix my 305, or buy a 350 short block and use Vortec heads his friend has that are almost new, or go with a GMPP crate 350 like the 330hp deluxe engine, and his boss can burn me a chip for it apparently. Obviously, I have to do more research along this end...

I was going to put headers on the car next spring, which would make the 305 more fun anyway...I dunno. I just hate spending that much on fixing a 114k mile engine...we all know this engine probably has a ton of life left in it though...

 

If you don't want to do any tuning just use an L05. 210hp and 300ft/lbs. of torque is not bad. Plus I believe that torque comes relatively low in the powerband which is good for the street. If you've got the Edelbrock intake and plan to use headers and cat back exhaust you'll get a few more ponies out of it. I had an 89 Silverado with an L05 and it felt like it had good power. The same goes for my sister's 95 L05 Silverado. I've got a Vortec 350 with a ZZ4 cam with TBI and it makes me wish I had just slapped an L05 in my Camaro. I'm having a hell of a time tuning it.

Gene

 

I've actually been thinking about doing the L05 all day now while I've been at work...under $1,600 for a rebuilt GM long block seems good to me. How much extra power could I get with a full exhaust, my TBI intake, open element and an ok chip from tbichips.com? They make specific chips for the LO3 to LO5 swap...

Thanks for your help!! Still on the fence, but getting closer...I don't want the tuning headaches, and 40 more HP stock to stock is a start...

 

Sounds like the entire back of the gasket is totally gone from what your describing. Does it also leak coolant a lot? The coolant passages are also in that area. I also assume that the engine runs real uneven, ticks LOUDLY, and smells of gas as well?

The L05 crate will make the car go from point A to point B, but you might consider getting something better, like a 350 HO and tuning the car. Youll be much happier with the results in the end.
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Tune it, and youll be thankfull that you didnt go with the L05. Even with a weenie cam, the vortec heads still where good enough for a high 5 second 0-60 time with my 350. The crate 350 was more like 7 seconds. Too slow.

 

Actually, no...it runs perfect, doesn't overheat, doesn't smell of gas and still gets decent MPG and runs perfectly smooth. That's the reason why I wonder if its really worth it to pull the engine and replace it, or just regasket the top end, add some headers next spring, and leave it alone for a few more years. I only drive the car 5-6k miles a year...this engine could last me quite awhile.

But again, why spend the $$$ if I can put it towards the labor for an engine swap? That's my dilemna. I'm waiting to hear back from the guy that claims his boss can burn a chip for me...I guess the guy had a '95 Silverado he did heads and cam on, and knows how to burn chips properly...something I lack.

3 things...

1) If I keep driving the car the way it is, can I assume the above situation will happen, where the gasket will get worse and possibly wreck the whole engine? I was just thinking about driving it for another month or so, adding 500 miles on it or so, and parking it until next spring when I'll have more $$$ and more knowledge on what to do...

2) The 0-60 of 7 flat...was that with an AT car? 350 TPI/ATs ranged from 6.3 - 7.1 in magazines, depending on who and what was tested. If I did a 5 speed LO5 combo with some bolt ons, I was hoping for something around mid 6s...is that unrealistic?

3) I've read all of the 305 to 350 swap stuff I can...I'm literally only limited by a) not really understanding chip burning still and b) who can do the swap for me. Hopefully this guy I'm waiting to hear back from will be able to shed some light on both of those things for me. After looking, the engine I really want to do is the 330hp 350 H.O. Above and beyond the basic things you'd need to go from an L03 to an LO5, all I'd need at that point is a different chip, and probably a fuel pump for that engine...is there ANY chance a place like tbichips.com could make an ok chip for the 350 H.O.? Does anyone have any experience along that line? Would an AFPR in combo with an ok chip make it fly??

This sucks...I've got a great running engine that with a little money will be fine again, or I can get into all this crap. I just don't know...

 

From what you describe, I doubt the gasket is blown. For it to cause an oil leak, the fire ring would have to blow completly out at the rear of the head gasket, and the entire gasket around teh oil drainback hole would have to blow completly out to cause an oil leak. Or the oil control rings would have to be so bad that it would cause oil to blow out with the intake charge whenever the cylinder tried to compress the mixture. The car would also run VERY poorly and make lots of noise, and probably spew massive ammounts of coolant as well. Basically this would be the most extreme type of head gasket failure. Id reach up and try to pull on those "pieces" of metal and verify that they arent just crud stuck to the motor. More likely your just seeing the edge of the head gasket coated in oil. Sounds like it just leaks oil like most other old SBC's on the road. The most likely places would be the china wall or the valve cover.

 

The 0-60 of around 7 secs was with my auto and my old semi-stock TBI setup.

The HO will require tuning by you. The motor is alot different then stock and will require hands-on tuning. You could also get away with raising the fuel pressure to around 20-30 PSI with the stock injectors and a good fuel pump, but the stock TBI will be a restriction.

Alternatively, you could leave your existing motor in place and get a better exhaust and some other mods and tune the engine yourself. This would be good for around 230-250 HP or so. Enough to get a 0-60 in the mid to high 5 second range. Maybe less with the stick. Its not uncommon for the stick cars to run in the 14's with some mods.

 

Thanks for the response. At this point, when looking at the total cost of doing a 350 swap (I really want to do the H.O or even a ZZ4...I know down the road if I did an LO5, I'd be unhappy), adding in the fact I need a fuel pump to do it right, the LO3 is staying for now...its getting ripped into tomorrow, probably.

I just spoke with our service manager, after conferring for a third time with our 2 best techs (one a former GM tech, one a 30 year Chrysler vet...its a Chrysler/Dodge/Jeep store), and they all pretty much swore on their mother that the head gasket is leaking. I know it seems extremely odd, and I will definitely let everyone know what they find wrong exactly. But I can see what they're saying...after letting it run for almost 2 hours, the only seepage at all was from the back of the head. The valve cover gaskets were replaced in the spring, and do not appear to leak at this point. Believe me, we've all looked it over really close, because I REALLY don't want to spend the $$$ to do this...but the leaking on the ground, the specks all over the back bumper, and the smell are driving me insane. Its a good running engine, it isn't a race car, and I'm reasonably confident I can run the engine another 20k or so (a good 4 years at the rate I drive it) before I get bored with it and commence the swap. This will give me time to learn tuning (I plan to play with the software this winter) so that when I am ready for the swap, I can get a ZZ4 thrown in that sucker when I have the money and make a pretty mean RS at that point.

My original goal for this car once the body and interior were finished (body is done, interior this coming spring) was to drive it for a few years, enjoy it in nice weather, and eventually do a ZZ4/T56/3.42 or 3.73 swap once I found a shop I felt confident with in doing the work. I guess this will buy me some time, and give me the chance to get the $$ set aside. As of now, I still owe $1,000 on the bodywork that was finished by our shop in June!!!

Thanks for the responses...you'll see me around here more as I start playing with tuning, and I throw some headers on next spring. I will let everyone know what the hell this leak actually ends up being...
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After reading your post again, one more thing...the 230-250hp range you mentioned...what would it take to get me there????

I already have an open element, TBI Performer manifold, and a Magnaflow cat and catback. Would headers and tuning really get me near the 230hp range??? What else would I need to get into that 230-250hp range?? If I could get there, I'd honestly be completely happy leaving the 305 in there, and doing a T-56 and 3.73 gear at some point...

 

Id get a leakdown test before id believe them that the head gasket is causing the oil leak. Id look everywhere else first. There are no pressurized oil passages in that area, just drainback holes that would need something to motivate them to spew oil rather then drain into the lifter vally. Its extremely unlikely that the head gasket is the issue, especially if the car runs good. Its much more likely that its the valve cover gaskets, even if they where replaced. Wipe the area down completly and check carefully where the oil is really coming from.

 

Thanks very much for your help on this. After reading your posts, I printed them out and brought them down to our service manager and had him read them. His advice was to drive the car home, then back here tomorrow morning (about 100 mile round trip, 90% highway), and we'd put it back on the lift tomorrow night. He did an awesome job cleaning it all up before he ran it on the lift on Friday, so we should get a pretty clear picture after I drive it home and back. Like I said, I trust these guys and they're great techs...but this is a Chrysler store, not a GM store...

If it is just the valve cover gasket, then I owe you one Whenever you have a chance, please respond to my HP questions above in response to your post...I'd love to get up to the 230-250hp range with this car. Like I said before, this isn't a race car...just a fun summer cruiser that I'd like to keep fairly original if I can get more power out of what's already under the hood! If I can get 230-250hp out of a 305, I'm more than content...and saved a ton of $$$.

Thanks again very much for your response...I really hope you're right!

 

assuming its a full 3" exhaust, you could probably get to around 230 with tuning. More if you swap the cam for something a little larger. Maybe a mild roller with around 210 degrees of duration at the intake.

 

I guess its pretty key for me to learn tuning then....the exhaust already in place on it is a 3" catback...I think the cat itself is a 2 1/2" inlet, 3" outlet...I imagine that's ok to leave?

I'll keep everyone posted on the head gasket issue...I'm dying to figure out what the hell is going on.

 

Mine is doing the same exact thing.Its an Lo3 with the edelbrock intake.Anyway its leaking on the driverside it looks like the head gasket but its not leaking any coolant doesnt have any power loss or overheat.Its a very small amount of oil that leaks but it leaves small drips.I looked to see exactly where its coming from and it looks like its from the head gasket but im not 100% sure??Its below the exaust manifold is where its leaking.When i changed the oil is when i noticed it.When i added oil it started dripping out but hasnt leaked as bad since.I am completly lost on what to do?

 

Guys I will almost garantee you that it's the china wall gaskets or oil pressure sending unit. When the china wall leaks it runs along the china wall then down the grove between the head and the block. A quick way to tell is to check and see if this flat area at the back of the intake is wet as well as the back of the block below the head. Like others have alluded to it would be about impossible to get an oil leak out of the gasket in this area without warping the head so bad that you made an oil and coolant milkshake.

 

So then, dumb question...what is a china wall gasket? Is this the same as what my friend referred to as a valley pan gasket? How hard is it to fix? Is this the gasket that runs along inside the intake, against each head? If so, that means I need to take the intake gasket off again...wonderful. Cheaper than a head gasket, but not a ton...

My apologies for my ignorance...I've never done internal engine work before. Thanks to anyone who can help...

 

The china wall is the curved part of the block that runs between the heads that seals against the bottom of the intake. If you have had the intake off before I will almost garantee you that it's the problem.

It can be a bit difficult to do correctly. There are gaskets available for this but using a good bead of silicone is a better option. You just have to be prepared to let the car sit for 4 hours before you start it or you'll blow out the silicone from crankcase pressure. Once it's setup you'll never have problems with it. This is how all major engine builders do it.

I suggest getting some repair manuals and reading up. No reason to go broke paying some one to turn a few wrenches.

 

BMmonteSS there is a remote possibility that 1/4 plug just below China wall on the driver side head surface is leaking. See photo - that's a full oil pressure line, but 'almost' always never leaks. It is close enough to oil pressure sensor and it is right under driver side head gasket in the back of the head!!!

//RF

 

I can almost promise you the oil leak you are seeing is from the china wall. My 305 is leaking after my TPI swap onto it. It has oil running down to both sides of the block. I ran it 400 miles this last weekend and lost about 1/2 quart in that time. Oil is dripping down the starter and down the oil filter. It is leaking from the little edges where the intake gasket goes into the china wall. Got a little stingy with the silicone because I only had a small tube and was too lazy to go get another one. LOL.

 

Well, because I want to do this right and not guess, I'm bringing it to them GM dealer I used to work for in a couple hours to have a tech I'm friends with take a look at it. I want a second opinion on it, and he's the best tech I know. For the $30 or so they'll charge to look at it, its cheap IMO...

I know the guy that did the intake before used an RTV sealer, and let it sit overnight for it to dry...at least alleviating a couple problems the intake installation would have had. Thanks everyone for your help...I guess I'll know more soon!

Assuming the china wall is my leak, I don't suppose smearing some RTV along the backside of the engine would do me any good, eh??? Someone on here awhile back gave that idea for when the intake was leaking!!

 

The best way to do it would be to remove the intake and clean ALL the old RTV off both the engine AND intake with a scraper and solvents. After that, lay down a thick clean bead of silicone on the china walls, slightly overlapping the the intake gaskets. This always produces leak free seals.

Ive used the rubber seals, and they tend to dribble. They're usually what you use when the car just has to be done ASAP and small leaks mean less then not having a ride.

 

I'm working on the tune. I've got EBL, an LM-1 and an Ostrich. Since I'm relatively new to tuning I probably should've started with a Vortec 350 with either an LT1 or LT4 cam instead of the ZZ4.

Gene

 

Well, after spending an hour over and underneath my car with the tech at the GM dealer, taking the distributor out and peeking down in, and a couple other things, guess what?!?!?!?! My car is SUPER rare...

IT NEEDS A HEAD GASKET

He explained and showed me exactly what happened. You can see the original shards of RH head gasket poking out of the back of the block we had seen original, and you can also see a couple small pieces coming out of the RH head. He determined that the head gasket itself, where it runs along the back of the head (its a "winged piece of the gasket...I forget the term he used, but he showed it to me on a diagram of a SBC head gasket) is actually disentegrating. He's never seen it happen before, but he claims the head has to come off and the gasket replaced...same as the other A tech that looked at it...

Everything else is fine...the valve covers, O-ring, everything. He is fully aware, as many have said on here, that there are no oil passages at the back of the block. However, he claims that because the head gasket is disentegrating along the back, the pressure in the head is allowing it to seep out. He understood what people on here were saying, in that it is not the traditional blown head gasket. But, after seeing it with my own 2 eyes, and seeing pieces of gasket poking out from the back and RH side of the head, I can see what he's saying...

17 year old gaskets...gotta love 'em. The nice thing is book time on the job is 9 hours, but they're willing to do it for whatever it takes him...which is probably a ton less unless I have a ton of rusty bolts. With that being said, I'm probably going to wait until after Christmas to do it (if the car is still on the road then), and do some research and consider replacing both heads with Vortec heads, and try to do some tuning between now and then. The engine runs too good to pull it IMO...tuning, some headers and possibly a set of heads won't win any drag races probably, but it will make it more fun to drive than now...

Just thought I'd let everyone know. He's never seen one either, but the evidence seems obvious at this point...

 

Its possible (but very hard) to damage the head gasket nearest to the china wall, which would be just like a leaking china wall. If that where the case, Id smear it with RTV. One thing about the head gasket is that the entire gasket is under tons and tons of force, which traps the head gasket material. It is unusual that it wouldnt break the seal at the fire ring, but it is possible for the rearmost part of the head to maybe bow up or something, or have been ground on in the past by an inexperienced mechanic. Same thing with the deck. If someone went to town with a grinding disk to take the gasket off (major no-no), it could create a low spot at the rear of the head or deck surface, which would unload the gasket and allow it to leak. Fixing this would require that you machine the block or heads, which makes very little sense given the high cost of labor. Take a feeler gauge and try to insert it between the head and gasket or block and gasket. If it goes in a ways and stops at the fire ring or near it, then its likely that the heads and/or block are junk due to the high cost of repairs. The only way to tell would be to lay a precision straight edge across the deck and heads. If the deck is OK, then you can just get a decent set of replacement 305 heads to keep it going. If not, then the 305 is trash.