install on gt40ps

I don't totally follow with the checking the dipstick for oil and not seeming that there's any in there? I'm just assuming that you meant it doesn't seem there's any coolant in the oil, so I'm going to answer based upon that assumption. The first thing you need to do is check your compression to be sure you don't have a leaky headgasket. A quick search on here will probably give you a couple dozen threads on how to do one correctly, if you've never done one before. The next step (you could actually reverse these, as the second step is easier) is to check for leaking intake gaskets. Spray some starting fluid around the mating surface between the intake and heads and check if the idle speed raises any. If it does, congratulations, you've found your problem. You may want to keep a fire extinguisher handy for this step because starting fluid is quite flammable, and you don't want your hard work to go up in flames. The car running like crap could also be attributed to a vacuum leak, so at the moment, I'd be leaning toward that being the problem, trying to be optimistic of course. Resetting the ECU probably isn't going to help much, as the car is trying to learn the new combination, just like it would if you were to disconnect the battery. Good luck, let us know how it goes!

Plug up the vacuum hoses that went to the smog equipment.

If it still is acting like a vacuum leak get a can of TB cleaner or carb cleaner and spray it around all of the gaskets and hose connections on the intake manifold and intake system. If the engine idles up then that is where it is leaking at.

Did you put thread sealing compound on the lower head bolts? if not then that might be where you are losing some coolant from. The lower head bolts run into the water jackets in the block.

Without sealant on the headbolts, your oil probably looks like a milkshake right now. Unfortunately, the only fix is to take it back apart at this point. You may be able to get away with doing one head bolt at a time, but you're running the risk of having to replace head gaskets anyway. You're probably just best off to do it all at once. I suspect you may still have a vacuum leak though if you didn't plug the hoses that went to the smog stuff like RYC CUKR mentioned.

Like stanggt said you might be able to pull the bolts one at a time and get them to seal up with the thread compound but sometimes they won't seal up cause they threads are wet.

Don't worry I made the same mistake and ended up having to pull the heads back off and redo everything and put all new gaskets in. So your not the first and won't be the last to make that mistake. My car exhibited the same type of symptoms that yours is. I was loosing coolant and couldn't find where it was going.

Good luck