Hey guys I currently have a 1975 Corvette that needed an engine, so I got an engine from the junk yard out of I believe an 87 Chevy Dumptruck. I know the engine has centerbolt valve covers where as the one I took out of my vette had the older style valve covers. Anyways I tore the engine down, sent it to the machine shop and had them bore the cylinders .040 over and go through the block and heads. I then put it back together, but re-used the edelbrock intake off my old engine and put it in my car. A couple weeks later I changed the oil and I found antifreeze in it, so I backtracked what I did and read on edelbrocks website that I was not supposed to use the cork end gaskets with their manifold so I pulled the manifold and used silicon instead, the car ran much better, but still had water in the oil. I talked with edelbrock about the fact that the manifold I have does not say it will fit my engine on their website, but they said if it bolts up correctly, which it does, its ok. Does anyone know if this is true? I pulled the manifold tonight and took all the gaskets out and it seems to fit pretty well without any gaskets. Tonight when I pulled it I did notice that the middle 4 intake bolts were very loose. Would that cause me to have a water leak even though it is far away from the water passages? Any help, suggestions, or comments would be greatly appreciated. I have been chasing this problem for too long now. Thanks.  

I just got the part number off my intake and it is 2104, which is the correct manifold for the engine, so I guess that part is ok.  

The manifold, if warped or cracked could leak at the crossover. It also seals the passages in the rear of the heads. The four center bolts would be the first to come loose because of the heat from the exhaust crossover. I assume you are useing the Fel-Pro printoseal gaskets and torque sequence to Edelbrock specs. Always delete the cross gaskets in favor of RTV. Did the machine shop magnaflux the block and heads? What kind of head gaskets did you use, and did you torque them properly? You mentioned that the manifold fit good without any gaskets, how does it fit with the gaskets in place? Are the bolts lining up? If all else checks out, pull the intake, make covers for the four water outlets in the heads, or borrow them from the machine shop, and pressurize the radiator. If it's pissing coolant, you will find it. If not then have the intake pressure checked.  

I used fel-pro printoseal gaskets, but i put silicone around the water passages on the intake side of the intake gaskets like it indicates in edelbrocks instructions, but did that defeat the purpose of the printoseal gaskets? I dropped the oil before I took it apart, left the pan plug out and put 15psi into the cooling system and it did not leak any coolant out of the pan, also the pressure did not drop. I believe I used fel-pro head gaskets, I cant remember. I am wondering if I would be better off just doing the head gaskets over again while im in there to rule that out. Its not much more work to do that.  

you said that the 87 dump truck had the newer style heads and you used the intake that was bolted to the older style heads on to your newer ones... arent the 4 middle bolts for the new style striaght down rather than angled like the older style,if so how did you even get them to bolt up?  

No, you're thinking of the later model Vortech intake bolt pattern.

Sounds like the manifold is warped and not sealing properly at the coolant crossovers. Try a different intake and see if you still have the problem.  

Almost forgot, there are several philosophies about using/not using the cork end gaskets. If you use them, you just have ot be sure to tack them in place, and use a little dab of silicone where the end gaskets meet the intake gaskets for proper sealing. I did this on my '92 Silverado, and haven't had any problems.  

I actually did use the correct manifold for the engine. I put it together over 3 yrs ago originally and forgot that I bought an edelbrock manifold for it brand new. The middle bolts are straight up and down, not angled like the rest. Are these bolts supposed to be longer? I remember they did not have as many threads to catch as the others.  

Did you use thread sealer on the head bolts? Not using it can get you water in the oil because the head bolts go into the water jacket and the water comes up the threads. Doesn't take much to get a leak especially when the water has pressure behind it. I use Locktite pipe thread sealer on all of my headbolts.  

I dont think I used any thread sealer on my headbolts. When I pulled the heads, pistons 3 and 5 were clean like they were getting water in them (steam clean look), the rest were normal looking. I didnt see any sign of a bad HG. I am sending the heads out to be pressure checked this week, as for the intake, I am going to check it with a straightedge to make sure it isnt warped. Can you guys suggest any headgaskets when I go to put this thing back together? The engine is bored .040 over, I dont know if this requires a different HG? I will pick up some thread sealer for the headbolts when I put it together also. Thanks in advance.  

my co-worker has a 400 and i remember him saying something about steam holes he had to add into the gaskets to match the heads. just a hunch  

ARP makes a great thread sealer. Don't forget to use some on the intake bolts too. On some motors they get into the water jackets.