H2Xmark

what is your water pressure?? that might be your problem if its to high. I have also had good luck with minor upgrades without ECM remap with changing the fuel pressure, i run aeromotive regulators and can change the pressure up or down without much trouble

KAAMA

iTrader: (1)

Heads may not be the cause and it could be other things when it comes to water in the oil as some have suggested, ....but you should know that if you have the stock GM cast iron rectangle port heads, that they DO have a tendency to crack between the seats. It happens like a roll of the dice and I have seen/heard of it happening to offshore boaters since the 1980's. If you're even remotely thinking of doing an upgrade with some new heads, then I would say the GM random head crack issue would be at least one good reason to replace them. Hope it goes well for you.

bobl

The intake may not be sealing well around the water ports. This is a common probelm if the heads/block have been machined and the intake has not. (look at the old gasket)

Grog

I REALLY appreciate all of the input.

Gris -
The intake has been eliminated as a possibility since I replaced very recently in a futile attempt to correct the problem. As it turns out, my original Whipple intake was just fine and never an issue. Like I said, I am in "replace everything mode".

Ecept -
The high dollar heads are a bit out of reach for now.....at least until I have a career change or quit drinking beer (not gonna happen). Whipple recommended basically the same heads. As I said, no can do...at least right now. I think too that *****in' heads with a stock cam would be a waste. Right?

Kennyo has a set of HP500 take-offs for what I think is a fair price and also think will work well for me as a direct replacement bolt on. What do you all think????

H2X -
My WOT water pressure is 19 psi. I also run the Aeromotive fuel pressure regulator. I hesitate to monkey with it without an air/fuel monitor setup and ......oh yea.....without knowing what the hell I am doing.

Kaama -
I've heard what you say about the GM heads and cracks before. Please see below.

I have some pretty good evidence that I have a leak at the intake manifold, although at this point, I have not ruled out a block or head crack.
Tonight, I bolted down the intake with some strips of Plastigauge at several locations (without an intake gasket). The center of the intake/head surface was a consistent .001" gap (pretty good I thought). As you move to the water ports, it varied all over the map (.002" to .004") around the small area around the water ports. The Mercruiser spec is .003 over a 6" span or .004" overall.

Also, what to you all think of this? Try to picture the situation that I am describing about the intake/head interface.....
In order for my intake gaskets (Fel-Pro 1211s 1275s, Mr Gasket, whatever) to not hang into the lifter valley at the water ports such that about 1/3 of the sealing surface of gasket around the bottom of the water ports is wasted, I need to trim about 1/8" off of the TOP of the gaskets so they will sit high enough on the head. If I don't rim the gaskets, the PrintoSeal ring (Fel Pro) will hang into the lifter valley. That doesn't sit right with me. On my heads (casting 14097088), the head sealing surface between the water ports and the lifter valley is only about 3/8". Am I making sense? Is this normal? Am I normal?

Thanks again for all of the input.

Greg

320es

If you're looking for perfromance gain don't dod the hp500 heads. They are the exact same heads that you have now. I am with everyone else though. I would look to other things if you are just trying to fix the milkshake problem. Are you running stock exhaust/cam?

bobl

That is the issue I'm referring to. Check how the intake sits in relation to that surface. My bet is at that point the gasket is not getting compressed or is overlapping. Since you've tried several intakes you can assume it's not the intake. Get the intake machined so it sits down further and I'll bet it fixes the problem

Grog

It is a stock cam and IMCO powerflow exhaust.

Right now, I am thinking that correcting the milkshake ploblem would make me happy, BUT........

How much performance gain can I expect with a set of CNC'd AFRs and ECU reprogram???? Remember, I want to keep my stock cam because I like the stock idle and do not want to pull the motor to change it.
For $700 + shipping I can have the HP500 take-offs and be back in business (that is, if the heads are truly the issue). On the other end of the spectrum is spending $1500 on aluminum Edelbrocks, or one step further, $3500 on CNC'd AFRs.


The gasket fits the intake fine with no overhang. Only on the heads. I think machining the intake will only cause a mismatch in the ports. The fact that stock gaskets need to be modified to seal around the water ports on the heads tells me the problem is with the heads.

I started thinking about what would cause standard BBC intake gaskets to hang over into the lifter valley. I think the only way this is possible is if a lot of material was shaved off of the heads at the block interface. Right?

Griswald

Have the heads been milled before?

I think what Bob and I are referring to is the gasket not sealing at the bottom edge of the head/intake. Shouldn't matter one bit if there is gasket material hanging over. In fact, most all applications do. That's why I asked if you'd tried a thicker gasket. That, or put some Ultra Gray pooky on the bottom edge and see what happens.

ECeptor

I understand completely. Sounds like finding a good set of the exact same casting number is your best bet.

FWIW, I high recommend that you DO NOT stop drinking beer!